I will however, continue writing about world affairs, defence, and security matters in a new place.

In future you will be able to find my analysis here.

WASHINGTON - The current crisis in US/Pakistan relations is not the first - but it is the most difficult one since 9/11, and it could easily be aggravated further by the intelligence arising from the raid on Osama Bin Laden's compound.

For this reason, Washington insiders are not so sure that diplomatic moves to ease the problem will succeed.

Senator John Kerry has just been in Islamabad asking for "action not words" from the Pakistani authorities. He says he has gained some agreement for practical steps but, apart from gaining the return of remnants of the US helicopter that was destroyed at the compound, has not yet specified what these might be.

This morning he and other members of the US Senate Committee on Foreign Relations will be holding hearings on Pakistan, including the question of how the billions given in aid could be used more effectively to buy the kind of counter terrorist cooperation that the Americans are after.

Juan Zarate, counter terrorist adviser to President George W Bush, argues that the kind of benchmarks that congressmen have advocated in the past for linking aid to performance on specific actions against militant groups could prove counter-productive in the short term because the Pakistanis consider this "humiliating".

He poses the further question, "what happens tomorrow if we have to go after Ayman al-Zawahiri?", referring to the former Al Qaeda number two and presumed leader after Bin Laden's death.

The question of what leads are thrown up by the intelligence trove from the raided Abottabad compound is now in itself a key factor in whether Mr Kerry and members of President Barack Obama's administration are able to soothe the relationship. Myriad questions arise from the material seized on flash drives and laptops.

Pakistani officials insist there was no contact between their Inter-Services Intelligence (ISI) and Bin Laden - but what about possible ties with the courier who owned the house and was the key figure in sheltering him?

Will phone numbers leading to ISI officials be found in Bin Laden's effects? Will there be intelligence that allows the CIA to quickly pinpoint Dr al-Zawahiri or other key figures who might now take control of Al Qaeda?

John McLaughlin, deputy director of the CIA until 2004, argues that even in this current difficult moment for US/Pakistan relations, America will reserve the right to act unilaterally against terrorist targets in Pakistan.

He believes though that ties can slowly be re-built with Pakistan, despite the fact that the raid, mounted without their leaders' foreknowledge, gave them their "biggest shock for a generation".

At previous moments of tension between the two countries, accommodations have been found. Intelligence about Al Qaeda suspects has flowed or the army has been sent in to one of the restive tribal areas on the Pakistan border. The US has signed off on new aid payments.

The tangled reality of the situation is made worse by the fact that Pakistani ministers, mindful of anti-American sentiment in their country, will often not admit publicly to their agreement to drone strikes or other steps. Many people I have spoken to here compare the relationship to a dysfunctional marriage in which both sides need one another but find the reality of daily life increasingly unbearable.

There are those who see ways though in which the two countries might navigate their way through the perfect storm of recrimination and resentment that the Bin Laden operation has produced.

Juan Zarate and some others believe that if the materials seized in the raid produce some nugget of intelligence that leads to the discovery of Dr al-Zawahiri or other key figures, the US may chose to trust the Pakistanis with this knowledge, and make them partners in acting upon it.

If the exploitation of the intelligence went wrong and a leak was suspected the US could use this to place further pressure on Pakistani ministers. But if it all went well, trust might be re-built. The problem is though that there are many within the secret side of US counter terrorism who, because of the way that Osama Bin Laden hid for years where he did, are no longer prepared to take that risk.

Watch Mark Urban's report on the state of US/Pakistan relations on Newsnight on Tuesday 17 May 2011 at 2230 on BBC Two, and then afterwards on the BBC iPlayer.

It's not a matter of blowing your way in and shooting members of al-Qaeda - the SAS and SBS are evidently quite good at that. It isn't even due to Britain's lesser intelligence gathering or aviation capabilities. All of these practical difficulties could probably be overcome - even if that required some American help.

The real issue for any British leader planning such an audacious and violent mission is to do with the legal constraints that exist on the way British intelligence agents and troops can operate.

Insiders say there are three areas where they are governed by quite different rules to the Americans: in passing or receiving intelligence that may involve the torture or killing of suspects; in using British troops to strike in countries in which we are not engaged in hostilities, without the permission of the government there; and in the rules of engagement that govern UK special forces operations.

Let's deal with those issues one by one.

The issue of intelligence and torture is an intensely controversial one.
Sir John Sawyers, Chief of MI6, has said publicly that Britain cannot pass secret information to countries that might use it to arrest and torture someone.

The ban is pretty clear. It is not just theoretical. I am told that two recent foreign secretaries obtained legal advice about passing specific information to governments that might mistreat detainees. In both cases the decision was to withhold that intelligence.

We know from Wikileaks that not too long ago Britain stopped American spy flights using British bases to fly over Lebanon because of the possibility that such flights might produce information that might be passed to Lebanese security agencies who might mistreat someone.

So while the world criticises Pakistan one might ask: if Britain had intelligence about that house in Abbottabad, would it have been passed on? Not to Pakistan, it seems. But what about to the US?

Now to that second issue - mounting military missions in foreign countries without the host government's permission. Those who've been involved with sensitive operations tell me that American drone strikes in Pakistan would not be considered legal under British law.

On one level it's pretty obvious that the UK takes a different view, since it has its own drones based in Kandahar and clearly does not chose to use them to hit targets in Pakistan. The issue, I'm told, is that the UK does not consider it legal to use them, except in support of UK forces involved in combat in an area of armed conflict. Pakistan, Yemen, or Somalia do not currently count as such.

Finally there is the question of the rules of engagement. When Task Force Black, the British special forces squadron group in Baghdad was operating, the rules governing their operations were eased somewhat. This allowed them to kill suspects on the basis of intelligence, rather than waiting for that person to 'demonstrate hostile intent', for example by grabbing a gun or shooting at them.

But even then, people who were there have told me, Britain's rules were tighter than the American ones. Two items of hard intelligence were needed about the presence of a particular violent terrorist, whereas the Americans would storm or bomb a house on the basis of one.

We know from Leon Panetta that, remarkably, there was no specific intelligence that Osama Bin Laden was even in that compound. It was rated as a 60-80% probability, based on circumstantial information.

And yet, on that basis some around the White House table were willing to advocate obliterating the building and those inside with bombs. A British government would have required more substantial intelligence.

Of course the British equipped with similar information about that compound, might have tried to exploit it in different ways. But a similar raid could have been blocked for a whole host of legal, political, and diplomatic reasons.

Amen to that - the Archbishop of Canterbury and millions of other Britons might say. One figure within the ring of secrecy told me, "our views on counter-terrorism are fundamentally different to the Americans' and we might as well just accept that".

That may produce a warm glow of virtue, but it also causes frustration in some of the more secret parts of the government and military machine.

But now the conflict returns to the shadows. The direction of travel, as the players exited the public stage tells us quite a bit about the next moves in this campaign.

In the first place there is the question of "sensitive site exploitation", as the experts call it. What exactly, or who was removed from the compound? Along with the door kickers or assault team of US Navy Seals, there would have been military and CIA people tasked with picking up anything of interest they could find as the gun fire ebbed.

Papers, mobile phones, computers, memory devices, and even the "pocket litter" of those found inside the house will all have been swept up.

When the Americans swooped on the rubble of the bombed house where they had run Abu Musab al Zarqawi to ground in June 2006, the sensitive site exploitation triggered dozens of additional raids.

In recent years, the CIA has become practised at entering the ruins of houses hit by its drones in order to sweep them for information. It has used its own Pakistani surveillance team as well as Americans to perform these searches, often working with very little time.

Might Monday's haul lead the Americans to Ayman al-Zawahiri, Osama bin Laden's deputy? It is highly likely that the two men were in some sort of contact, although they would have been extremely careful about it.

People in Inter-Services Intelligence - the ISI or Pakistani military intelligence - have told a BBC colleague that the Americans took one living person away from the compound on their helicopters.

They speculated that this might be a surviving Bin Laden son. If true, this capture could itself prove of major importance.

Of course, as the US seeks to capitalise on the intelligence finds from its raid, the question of Pakistani co-operation and access will loom all the more important.

Those who know the secret world suggest that while politicians may not chose to make too much of an issue of possible ISI knowledge of who was resident in Abbottabad, the spooks are likely to use the suspicion of possible complicity or incompetence by the Pakistani agency as a way of keeping the pressure up on them to help.

In truth, the Pakistanis have had to live with the fact that the CIA has gained considerable power to operate independently in their country.

After the arrest earlier this year of CIA contractor Raymond Davis in Lahore, after he allegedly shot dead two men, the Pakistani authorities had tried to limit the agency's freedom of action.

However, as the Bin Laden raid showed, the CIA retained considerable autonomy. Its personnel, contractors, and Afghan auxiliaries operating in Pakistan and the Afghan border region may amount to thousands.

It operates the Reaper drones used to hit militants in the Tribal Areas from Pakistani air bases, and its air wing moves its people around the region independently of the US military or any government.

The most likely explanation for how the American helicopter assault force reportedly refuelled at a Pakistani air base on way to its target is simple that movements of US aircraft in the night across Pakistan have become so commonplace that procedures are in places to prevent this causing incidents.

So as the CIA and ISI survey the scene, their mutual suspicion has, if anything been reinforced. The Americans have the advantage for the time being, but few in Pakistan will have relished what happened in Abbottabad, and the friction caused may prove to be the biggest obstacle to exploiting the leads gained in the raid.

The White House wants cuts of $400bn over the next 12 years - and that comes on top of more than $100bn already sheared from the Pentagon budget since this administration came to power.

The outgoing defence secretary, Robert Gates, has warned that the military should not be viewed as the place to solve America's federal deficit problems.

He also made explicit his view that the US should not be drawn into a big military commitment in Libya. Increasingly Mr Gates, a veteran of beltway politics, seems to have surveyed a landscape of growing global turmoil and diminished US resources with a weary resignation.

In a way, the foreign policy elite in Washington (and London for that matter) appears to have divided along the lines of pessimistic apparatchiks and politico optimists.

As a former director of the CIA and defence chief for both Presidents Bush and Obama, Mr Gates personifies the sort of experienced insider who surveys events in the Arab world and can imagine all of the ways revolution in Yemen, Egypt, or Syria could go horribly wrong.

His successor, Leon Panetta, as director of the CIA, it is true, has been exposed to the professional pessimists of that agency for the past few years.

But in his bones he is a democratic party stalwart, and a veteran of many political battles in Congress.

Mr Panetta is more likely to share his president's excitement that the Arab Spring offers an exciting hope of change and renewal than many of the hard bitten case officers he will leave behind at Langley.

If your budget is being cut that deeply, it certainly helps to be an optimist.

General David Petraeus is now widely expected to step into the director's shoes at CIA. He does not fit easily into the category of optimist or pessimist and he is certainly no politician. But having commanded US forces in Iraq, then across the Middle East, and most recently in Afghanistan, assuming along the way a good deal of personal responsibility for the strategy being pursued in those places, he is unlikely to feel that it is all going horribly wrong.

Both Mr Panetta and Gen Petraeus will be moving into their posts at a uniquely difficult time. America's on-off air strikes in Libya have shown how reluctant Washington is to become drawn into new military commitments.

As it becomes clear that the drive to balance the books will mean sitting out crises more often the dangers are clear enough: of waning influence; a drop in military morale; and increasing difficulty in foreseeing which of the many global crises of the next few years will prove impossible for the US to sit out.

I had gone to meet Lt Gen Suleiman in his office overlooking the harbour in Tobruk, and he was commenting on the decision to set up a special fund to help the fledgling government that has emerged in eastern Libya.

The general, who is a keen student of German general Erwin Rommel's campaigns in North Africa, and I were discussing what needs to be done in order to create a proper army.

He emphasised the need for a structure of battalions, brigades, and supporting units, improved communications, training, and new weapons.

So far the enthusiastic amateurs who have raced up and down the coast road - one day seemingly victorious, the next fleeing for their lives - have made few concrete gains.

Their incapacity, combined with the stepping back of the US from attacking most ground targets (and thus the disappearance of Nato's most powerful instrument for beating Colonel Muammar Gaddafi's forces) has given rise to widespread fears of stalemate.

British and French leaders have resorted to cajoling allies to provide more ground attack aircraft, and thinking more seriously about giving more direct military support to the Libyan revolutionaries.

Both nations are now actively engaged in defining the needs of this new army in order to raise its effectiveness.

At a non-descript address in Benghazi, an embryonic defence ministry, called for the moment the Military Council, has been formed.

It is headed by General Abdul Fateh Younis, formerly Col Gaddafi's Interior Minister, and has as its chief of staff General Omar al Hareri.

Several other key figures have been co-opted onto the council including Lieutenant General Khalif al Haftar, another former regime general who spent two decades in exile in the US.

After a brief power struggle with Gen Younis, Lt Gen Haftar has been given the post of commander of ground forces or number three in this hierarchy.

In the office building where they now work, British and French advisers scurry around. They are unarmed and wear civilian clothes.

The advisers soon diagnosed a complete lack of command and control over the rebel forces as their key weakness. They have therefore been assisting the formation of the military council and have provided satellite phones and other communications equipment in order to ease contact with people in the field.

So far, Nato countries have been hesitating with arms supplies, and are concerned not just to get the legal formalities right, but also to work out how they might train raw Libyan troops to operate new weapons quickly enough to have any effect on the contest with Col Gaddafi.

When I asked Lt Gen Haftar about arms shipments, he said, "we have received some promises... but nothing so far".

So the revolutionary army has been reduced to scavenging the former regime's bases and its fleet of "technicals", or armed pick up trucks, now features a bizarre array of weaponry ranging from rocket pods taken from helicopters, to light anti-aircraft guns.

While the task of forming a more effective army gets underway, the revolutionary authorities rely on Nato to keep Col Gaddafi's troops at bay.

Lt Gen Haftar says that his officers give Nato co-ordinates for enemy forces that need to be hit, and the alliance then takes action. The Americans were initially reluctant to act as the "rebel air force" but as the alliance's involvement in Libya deepens, the policy has shifted.

If the regime holds out in Tripoli and the current stalemate endures, what will Nato try next? The bad tempered briefing that has been conducted by some British and French officials against Italy and Spain for not providing more military support suggests there is nervousness about how long even the current, reduced, air campaign can go on.

Gen Mahmoud, sitting in his office in Tobruk, argues that a British military training mission would be most welcome. He remembers working with such a team back at the time of Col Gaddafi's 1969 coup, and asks rhetorically, "We know them, why not?"

Tobruk itself is an iconic place for the British. It was there in 1941-2 that Allied forces were besieged by Rommel's Afrika Corps. The place fell to those besieging forces but was later recaptured as the British 8th Army swept across North Africa after its victory at El Alamein.

Victory in that desert war required strategic patience and vision. The question now is whether the Libyan revolutionary forces and their Nato allies share those qualities.

People on the streets say they are bewildered at what Nato has done, but they are also adamant that they do not want foreign troops here.

I understand that the aircraft responsible were either French or Canadian, although Nato refuses to specify the nationality.

The incident has changed the atmosphere here in many ways.

When General Abdul Fateh Younis, effectively the commander of the rebellion, said on Thursday at a press conference that it did not need or want soldiers from other countries to become involved, Libyan journalists burst into applause and started cheering.

It is also only fair to say that many Nato countries would have deep reservations about the possible "mission creep" involved in putting forward air controllers or training teams on the ground.

Although it is widely assumed that some British, US, and French intelligence and special forces personnel are here, it seems that their role is confined to maintaining high level communications with the rebel leadership.

If not, how could Thursday's mishap in which 20 armoured vehicles were sent south by Gen Younis without Nato knowing about it have happened?

The general and the alliance spokesmen flatly contradict each other over whether or not the rebels passed on information about their intended assault. But spotters on the ground would most likely have prevented yesterday's error.

Given the recriminations, and the reluctance of Nato to get drawn into acting directly as the rebel air force, it does not seem like any rapid change in this confused situation is possible.

There have already been three accidental Nato strikes on rebel columns, and it is quite possible there will be more.

As the casualties in these incidents multiply, it is bound to feed the doubts that some Nato members have harboured about this campaign since the outset.

In addition to the likelihood of accident, the current limited state of co-operation is also likely to slow down a military resolution of the conflict.

The sharp reduction to the number of missions being flown by US aircraft will have a significant effect on the damage being done to Colonel Muammar Gaddafi's forces.

The initial "coalition of the willing" air assault on Libya (in which the great majority of the ordnance was delivered by America) hit air defence and command installations.

But knocking out anti-aircraft missiles, rusting migs, or bunkers has had a very limited effect in the Gaddafi forces' ability to harm the rebels.

Ground operations consist of fast moving attacks with pick up trucks, armoured vehicles and artillery. The number of individual targets of this kind belonging to regime forces probably runs to several thousand.

Perhaps a few hundred have been destroyed so far and the British, French and few other countries still attacking ground targets (as opposed to patrolling Libyan airspace) can add two or three dozen to that tally each day.

At this rate of attrition it could be a long time yet before Col Gaddafi's forces are broken.

But UK Prime Minister David Cameron and Foreign Secretary William Hague have been predicting that this dispute too will be solved in the coming days.

For the moment then it remains a "two tier" operation, as I characterised it on Sunday, in which Nato agrees to do the easier bit - the flying over North Africa in order to knock down any of Colonel Muammar Gadaffi's aircraft - while leaving the trickier business of bombing forces in built up areas to the "coalition" of the US, UK, and France.

This difference of views, even if it persists beyond the few days predicted by Mr Cameron, ought not to wreck the campaign, because that smaller group of US-led nations can keep dropping bombs or launching missiles.

Col Gadaffi is hurting badly, and whether his survives for days or longer, he cannot win in the sense of re-establishing his control over the whole of Libya by force.

So why are we even writing or talking about this political disagreement then? Perhaps its greatest significance is as an example of the political, and perhaps even moral, weakness of many members of the Western alliance.

After all, the position of the countries that do not want launch bombs or missiles against ground targets is that they would like somebody else to do it for them. Several Nato countries, including two key members (Germany and Turkey), are simply convulsed with doubt about killing people on the ground.

These countries have approved the idea of a no fly zone, and accept that UN Security Council Resolution 1973 gives it a strong legal basis. They do not mind killing Libyan aircrew in the sky, by shooting down their aircraft, and they are quite content with the idea that the suppression of air defences (ie strikes against surface to air missile sites, command bunkers, or airfields) needed to allow the no fly zone to be established be done by someone else.

It would be one thing to oppose the whole idea of this operation - to object to all of the military action carried out, regardless of what military/political label is put on the command arrangements.

But while Germany, Turkey, and some other nations voiced doubts about the idea (and Germany abstained in the UN vote over resolution 1973), they do not feel strong enough to argue against the whole enterprise or indeed to use their veto power within Nato.

So the last minute argument to persuade these countries to accept that the whole operation needs to be placed under a Nato mandate continues. Meanwhile, many senior people in the alliance suspect that this political division will only become a serious issue, if somebody's aeroplane hits the wrong target and many civilians die.

At this point, having the whole operation under a Nato banner could become a liability, because one of the doubters might lead a movement for the whole thing to stop before its objectives have been met.

This is essentially what happened during the 1999 Kosovo air campaign when a number of countries tried (but failed) to start a movement for a "bombing pause" when the air offensive dragged on, claiming many civilian lives.

The idea that some innocent people may die in order to save the many is explicitly embraced by the Libyan rebel leadership and ought not to be a moral revelation to anyone who has thought about political philosophy.

It is after all the basis upon which developed societies accept all kinds of risks, from the one that speeding emergency services vehicles might run down pedestrians to the understanding that certain types of surgery end up killing rather than curing the patient.

So the present situation arises from political confusion - an understanding that the intervention is justified and therefore should not be blocked sits in conflict with an underlying sense of pacifism (in Germany), or Islamic sense of community (Turkey).

It all simply adds to the pressure facing those carrying out the air operations not to make mistakes. Decision makers in the UK, France, and America know also that it impels them to get this over with quickly - and it is at the intersection of military and political risk, that rushing for a result produces a terrible error, that the greatest hazard to this venture may lay.

That underlines deep political differences among Western nations about how much force should be applied and what the "end state", or aim of the violence, should be.

Watching the way that the initial strikes against Libya have been mounted, the existence of this dual approach to the problem has become quite evident.

It has also conditioned the types of weapons, and bases employed.

UK, French and US forces have started a "coalition of the willing" operation against Col Gaddafi's forces that has included bombing air defences and at least one ground column heading for Benghazi.

Several of the other countries that met on Saturday in Paris to discuss "support to the Libyan People", do not wish to drop bombs on that country or, in some cases, allow their bases to be used for that purpose.

So the offensive that began yesterday has involved the use of long range attacks and avoided the Nato chain of command. It is being co-ordinated by the US Africa Command, under General Carter Ham.

US briefings suggest that this wave of strikes has been sufficiently effective to allow patrolling of the skies over North Africa to begin soon, and this will mark the second stage or tier of the operation.

The wider international operation to enforce the no-fly zone will be done through the Nato chain of command, and will be managed by US Navy Admiral Samuel Locklear, as we revealed on Friday's Newsnight.

Both commanders are Americans - the general operating through a national headquarters, and the admiral through an alliance, ie a Nato, one.

The use of Gen Ham's headquarters for this purpose is sufficiently sensitive for the French to be denying they are under US operational control.

The methods used to attack the Libyan leader's forces during the first 24 hours relied upon flights from France, the UK, and the US, as well as cruise missiles fired from the high seas.

In other words, they did not involve launching lethal attacks from the territory of that wider club of nations that met in Paris, or indeed of other Nato members.

Military commanders believe that the "coalition of the willing", will be able to bring sufficient combat power to bear in order to cause the fall of Col Gaddafi; the aim that the US, UK and France share.

But if that does not happen relatively quickly there could be growing pressure on other countries to allow their bases to be used for attacks, since the methods used during the initial wave of strikes were relatively inefficient.

The flight of RAF Tornado GR4's from Marham in Norfolk to hit Libyan air defences has been lauded as an impressive feature of airmanship - but it soaked up much of Britain's air-to-air refuelling capability and evidently would have been more efficiently conducted from bases in southern Italy.

France too has stretched its limited refuelling capability in order to hit targets from its own national territory.

Sources suggest that although many RAF and French aircraft were in action during the first 24-hours of the conflict, the number that actually dropped bombs or launched missiles against Libyan ground targets was fewer than one dozen.

US B-2 bombers, and 112 naval cruise missiles were needed to add weight to attack.

If Col Gaddafi does not fall quickly, this level of pain will have to be raised. Instead of hitting a few dozen military objects each 24 hours, the coalition will need to strike many times that number.

Anticipating this, France has ordered its aircraft carrier strike group to sea. The Charles de Gaulle, with its embarked air wing including 18 fast jets, will be able to sail close to the Libyan coast where in-flight refuelling needs will be minimal and the aircraft will be able to reach fleeting targets far more quickly than those launched from France itself.

Although the US has not yet used carrier aviation in this offensive, it is moving to be able to do so. Britain, having recently retired the Ark Royal and its Harrier force, lacks a similar option.

Italy could become a vital part of this operation. However it is not yet clear that the Italians have allowed their bases to be used for bombing attacks (as opposed to patrolling the no-fly zone once it is firmly established, flight refuelling, surveillance, or electronic warfare missions). Reports that some Italian seamen have been seized in Tripoli make their government's dilemma all the harder.

As for the wider coalition effort, including possible arrival of combat aircraft from Arab countries, it has not yet begun.

France in particular is anxious that the Arab public does not see this as a similar US-led operation to the ones which invaded Afghanistan and Iraq, so it has strained every diplomatic and political sinew to take a leading role in the initial phase.

In the coming days though the limitations of the UK and France to apply their military power, such as it is, in pursuit of the Libyan regime change agenda could become clearer if Col Gaddafi's people cling on.

All manner of political tensions might then result, from pressure on other Nato allies to join the strikes to a growing sense that American might may be necessary to finish something that the White House was for weeks very reluctant to get involved in.

In a sense, Prime Minister David Cameron's championing of the plan is pure Tony Blair - it is precisely the type of liberal intervention envisioned in the former prime minister's speech to the Chicago Economic Club in 1999, which put forward a case for dispensing with the usual rules about non-interference in the affairs of another country if its people were being brutally repressed.

Indeed, the new resolution is such a striking example of this doctrine (which was enshrined in changes to the UN Charter in 2005) that many people may be asking why similar plans are not afoot to sweep the skies of Zimbabwe, Iran, Burma, or indeed Bahrain.

Of course that is not about to happen, but the reason it will not is not connected with the political or legal dimensions of this doctrine but with the harsh real politik that determines that one UN Security Council veto power or other would step in to stop something similar happening in any of those cases.

It seems odd that Mr Cameron should be acting this way since he had gone to such lengths to reassure the electorate that he would take a longer and harder look at any case for the commitment of British forces overseas than his Labour predecessors had done.

Of course the new prime minister's message was partly one about not following the United States blindly into military intervention, and he can certainly say with some justice that this initiative has been driven by the UK and France, not by the US.

However, by championing the case for the Libyan intervention when offers of US support have been lukewarm, Mr Cameron has raised the stakes in almost every way.

If the Libyan regime collapses quickly, then the UK prime minister and France's President Nicolas Sarkozy will, quite rightly, be able to claim much of the credit.

It has been clear from the outset of this crisis though that Colonel Muammar Gaddafi is not going to skip off in the style of President Ben Ali of Tunisia.

If he is able to survive the next few weeks - with or without airstrikes - questions will soon multiply about the how long the no-fly zone can be maintained, what the price for its lifting needs to be, and whether the US role in sustaining or expanding it will become central.

There are dangers, then, that Mr Cameron and Mr Sarkozy may be writing cheques that could be difficult to honour.

The idea of a British prime minister dragging America into a new war would be an impressive political feat, and a fertile subject for comedians, but ultimately would probably not do him or US President Barack Obama much good politically in the long term.

These risks are all the more complex for the British government because it is engaged in cutting its armed forces under the Strategic Defence and Security Review.

The retirement of Harrier jets and the Ark Royal, that could have been very useful in imposing a no fly zone, has already attracted widespread comment.

Now the RAF is being asked to send its people into battle at the same time that it is making hundreds of aircrew redundant.

The RAF is of course doing everything possible to send endangered aircraft types such as the Tornado, or Sentinel, and Nimrod R1 surveillance planes. It may hope to earn parts of its fleet a reprieve.

So, just as success will offer Mr Cameron the chance of a major diplomatic coup, the
possibility of it not going to plan could be toxic.

It is one thing to act energetically, and independently in ones diplomacy, but quite another if doing so creates for the military taxing additional missions which your own government has undermined their ability to fulfil.

It is a familiar dilemma for decision makers with echoes of the Balkan conflicts of the 1990s, and even of the Soviet occupation of Afghanistan in the 1980s.

The cynical view is that what we have seen so far has simply been verbal grandstanding by leaders who know there is public alarm at what is happening in Libya, but do not wish to commit themselves to military action there.

France's President Nicolas Sarkozy appears to have been playing this game when his people briefed last week that he was proposing air strikes against Colonel Muammar Gaddafi's forces.

However, those emerging from last Thursday's Nato meeting in Brussels were quite adamant that neither France nor any other ally had proposed air strikes. The story seems to have been nothing more than hot air.

During the Bosnian War of 1992-5 it took years for a position finally to be adopted that Nato should put boots on the ground, and that military action was needed to curb the Bosnian Serbs.

It was such a prolonged, painful, and unedifying saga that it is little wonder that some of the key decision makers who endured it - such as former defence and foreign secretary Malcolm Rifkind - are determined to move faster this time.

He has today advocated in the Times newspaper arming the Libyan rebels.

Will that work quickly enough though? When Western countries decided in the 1980s to provide (covertly) anti-aircraft missiles to the Afghan resistance it took the best part of 18 months for the plan to come to fruition.

At one point Britain even flew the Afghans it had selected for training to a Gulf country, where they were taught how to use Blowpipe missiles.

Given the advances achieved by Libyan government forces in the past week, it is obvious that there is not time for that type of assistance. The help has to be given urgently or not at all.

It may be that the best thing the United States and European Union could do would be to aid the rebels by setting up a secure communications network, providing them with intelligence, and encouraging their leaders to think strategically about the defence of Benghazi and other strongholds in eastern Libya.

A handful of liaison teams, comprising no more than a few dozen personnel, would be sufficient for this.

The best prototype for this type of operation would be the clandestine assistance given to the Northern Alliance in Afghanistan following 9/11, when teams of CIA and special forces galvanised an offensive against the Taliban that unseated them from power.

Of course the saga of Britain's ill-fated special forces mission to the Libyan rebels shows that such a move would be far from risk free. What is more, the key ingredient that was present after 9/11 - US willingness to risk its people in the field - appears to be absent today.

Even if MI6 and the CIA are still willing to take the risk of travelling into Libya, they would not be able to call upon air strikes in the way that they were in Afghanistan in 2001 - not yet anyway.

Indeed a couple of bolshie Libyan farmers seem to have upset Britain's plan to help the resistance leadership - or its first attempt to do so.

So the options today, like those in the Balkans, are far from simple or risk free. But if they are to have any effect on the outcome in Libya, they need to shift from the rhetorical to the practical within days.

This town is its capital. This afternoon, I was out in the Bolan Bazaar, which was a riot of oranges, nuts, cell phone cards, and all manner of merchandise.

It is not that I have a deliberate desire to avoid North Africa or the Gulf, and the extraordinary events going on there (far from it); it is more that these trips take time to organise.

This one has come up after months of preparation, and when good opportunities are available I don't like to miss them.

The main mission of the BBC team I am with here is to gather material for a special one hour documentary charting the history of the Western intervention in Helmand since 2005.

But I will also be preparing something for Newsnight that we hope to put out in the next few weeks.

There has been quite a lot of talk of progress here in recent months.

There have been false dawns before, so even though the conversation now tends to be littered with caveats it is nevertheless beginning to assume a steady up beat pattern.

You could easily argue that there ought to be progress because the resources now being thrown into this fight are enormous.

There are more than 30,000 Nato troops in Helmand and Afghan security forces nearing 20,000.

The Soviet army garrison here was just 2,500, with its Afghan allies numbering about twice that number.

Today's foreign intervention is much more ambitious in its scope though. Whereas the Soviet army simply aimed to hold this town and the nearby commercial centre of Gereshk, Nato is trying to pacify the whole province, while improving its poor governance.

So, my task in the coming days will be to see whether this effort is indeed bearing fruit, as its advocates claim.

We've got a much better idea in the past couple of days about the political process that is underway in Egypt.

We can also see more clearly how the principal forces in this battle - Egypt's security establishment and the Muslim Brotherhood - are trying to out manoeuvre one another.

The Brotherhood appears to see the current crisis as an important stage in its decades-long struggle against repression and is not aiming for a rapid solution.

Instead it is trying to soothe those who might be alarmed by its rise (the secular and Christians at home; those abroad who fear political Islam) with carefully formulated political messages: the Brotherhood will not put forward a candidate for the presidency in the polls due in September; it will respect all cultures; it will respect Egypt's international treaty obligations.

At the same time, one can infer that the Brotherhood wants to improve its representation in parliament substantially. Candidates affiliated to the Brotherhood did well in 2005, and are likely to do even better in the next elections, particularly if the regime is pressured into allowing a fair campaign.

The security establishment, for its part, is deeply suspicious of the Brotherhood, although it appears ready to allow it greater freedom of action. The old guard, is now personified by vice president General Omar Sulayman, who, the Wikileaks cables show, has frequently warned the US about the dangers presented by the Islamic group.

At the weekend Gen Sulayman held talks with the opposition, including the Brotherhood. This was progress, no doubt, but it is easy to imagine the suspicion with which those around the table regarded each other.

The opposition declared it was unhappy with the outcome of the talks and that demonstrations would continue. The security establishment, for its part was ready to throw some of its members to the wolves, allowing investigations to move ahead on several key officials.

What all of this suggests is that we may now be in for a prolonged period of political manoeuvring. The American envoy, apparently sensing this, surprised many by stating that president Mubarak ought to remain in place until, September to oversee the transition.

The coming weeks or months promise all manner of tough talking about the elections, constitutional changes, and the fate of many leading personalities including President Mubarak himself. Protest and violence will be an intrinsic part of this negotiation.

As the security bosses and the Muslim Brotherhood seek their accommodations, both the president and many of the protesters in Tahrir square may prove expendable.

Sending club wielding gangs of "supporters" into action has denied the pro-democracy protestors the kind of iconic image of oppression that come out of China when a man stood in front of a column of tanks in 1989.

Earlier this week, I wrote about why we should not under-estimate the forces of conservatism in Egypt.

But like many of a Western mindset, I supposed that uniformed servants of the state, like the black-clad Interior Ministry forces who we saw in action last week, might form the visible face of a crackdown.

It is clearer now why protestors in Tahrir Square had recently been searching those joining the protest, looking for weapons or police ID cards.

They were not being paranoid, they understood that President Hosni Mubarak and his newly installed vice-president, former intelligence boss Omar Suleiman, had some other options at their disposal.

The use of agents provocateurs to discredit political opponents by sparking acts of violence goes back centuries.

What would be new though is using entire crowds to clear the streets of demonstrators, when the fact that the world is watching makes it impossible to do that with tanks or riot police.

With these "supporters" Mr Mubarak can deny that he has ordered a crackdown.

He can also claim to Western governments who urge him to rein them in, that they are not under his personal control and that his critics are exhibiting double standards about street protest - it is fine when they are anti-Mubarak, but not when they support him.

Of course the arrival of this new force on the streets has infuriated pro-democracy protestors. Many are predicting that it could lead to an ugly escalation in violence.

As night fell in Cairo, the air was crackling with gunfire as the army fired "warning shots".

The fact that the army today issued a statement urging the anti-Mubarak crowds to go home begins to look like part of a joined up strategy.

The anti-Mubarak campaign may well be tempted to use more force in response to today's developments - and there are some signs that this is happening spontaneously in Tahrir Square and elsewhere.

But if street violence is met with counter violence, then Egypt's security bosses would have their excuse for a more conventional type of crackdown - and will be able to cite "growing anarchy" as their excuse for doing so.

They are the generals, businessmen, and political fixers who run the country, have prospered for decades at the expense of others, and have the most to lose from revolution.

These are the kind who told President Ben Ali of Tunisia that it was time to go (because their interests were threatened), and who to a considerable extent still wield power there, and suppress the demonstrations in Tunis that are now largely ignored by the foreign media.

By appearing with his security chiefs on TV on Sunday, Mr Mubarak sought to convince everybody that he retains the confidence of Egypt's oligarchy.

Their continued support has come at a price, including the appointment of Omar Suleiman, the former intelligence chief, as vice-president.

Gen Suleiman personifies Egypt's "permanent government".

As a former boss of the Mukhabarat intelligence service, he knows better than anyone what makes Egypt tick.

He played an important role in negotiating the ceasefire than ended Israel's Gaza War in 2009, and has extensive contacts with foreign diplomats, spymasters, and business leaders.

At the moment - and clearly events have been moving with great speed in the region, so this may change - Mr Mubarak is just hanging on, and the oligarchs have lined up a possible replacement in Gen Suleiman.

The army has secured key installations in Egypt's cities, and whatever support its members may feel for the country's unemployed or down trodden masses, the military has held together, without units going over en masse to the opposition.

The Egyptian army prefers to remain in this reactive role - its statement that it will not fire on the people makes plain it will not clear the streets.

If it was ordered, that task would most likely have to fall to the interior ministry's 400,000 strong paramilitary forces, who have re-emerged after spending the weekend in barracks.

So long as these forces - totalling nearly one million armed men - remain solid, the country's permanent government will not have to cede power.

They may choose a different front man; they may concede some tangible influence to a newly elected parliament; but they will prevent radical transformation of the country.

They will protect their economic privileges, and block any wholesale power grab by Islamic extremists.

If though the army, interior forces and Mukhabarat fracture, then a truly revolutionary situation may arise.

Mr Mubarak or his new vice-president might retain the support of the generals, but if the forces are placed in an untenable position - for example by having to mount a large scale violent crackdown - a revolt among middle ranking officer (such as colonels and majors) could ensue.

This was the type of change that brought radical transformation to Egypt and the wider Arab world in the 50s and 60s when "colonels' coups" spread from Cairo to Baghdad, Damascus and Tripoli, sweeping away an old elite.

Back in the 50 revolution brought a pan-Arab ideology to power: Baathism.

Today the vibrant currents of thought are Islamic, and democratic.

We can only guess whether the current events will produce a "1989 moment" in which democratic values spread out from Egypt, as they did from Berlin at the end of the Cold War, or a "1979 moment" involving an initially broad-based democratic revolution being hijacked by Islamists as it was in Iran.

But the people who would lose most from either course - the Cairo elite - will not give up easily.