THE FANTASY of nuking Iran is never far away from the minds of those who fashion US foreign policy. And let's face facts, it can be done, if not by them then by their proxies, the Israelis, whose fingerprints are all over last year's destruction of a North Korean-built reactor in Syria. For no doubt good operational reasons, the Israeli Defence Forces (IDF) continue to keep schtum about the whole business; all that we know is that the US provided the intelligence.

The matter has even cropped up on Hillary Clinton's radar judging from her recent remarks about the need to "obliterate" Iran should it ever pose a threat to the security of the Middle East. If by any chance she becomes president, the man responsible for carrying out her wishes will be General David Petraeus, who has been nominated as the next head of US Central Command (Centcom), the general responsible for directing policy in the Middle East, the Gulf and Afghanistan. In other words, he's the head honcho and, although he takes his orders from the commander-in-chief in the White House, nothing will be done without his say-so.

In most respects his appointment is not unexpected. In President Bush's eyes Petraeus can do no wrong, having at last brought some sense and cohesion to the counter-insurgency operations around Baghdad.

While the "surge" has not been the overwhelming success claimed by cheerleaders, such as Vice-President Dick Cheney, the policy has at least helped stem the tide of violence, especially in Anbar province where Sunnis are now co-operating in the fighting against al-Qaeda terrorist groups. It has also given US forces on the ground that most useful of military commodities - hope.

In so doing, Petraeus has also torn up the rule book by rewriting the Army Field Manual that controls US military doctrine. It was a seismic shift: out went big armoured operations and in came a new reliance on the dynamics of asymmetrical warfare. Overnight, or so it seems, US commanders found they had to learn the most important message of counter-insurgency warfare: if the government doesn't win, it loses; if the insurgents don't lose, they win.

Equally radically, Petreaus insists that all conflicts have to be viewed within a political and historical context and, apparently, he has also recommended officers and senior non-commissioned officers should be able to speak at least one language other than English or Spanish.

All this takes the new Centcom commander in the direction followed by other thinking soldiers such as Frank Kitson, the godfather of low-intensity warfare, but there is still much to know about his wider geo-strategic thinking.

In Iraq he has made it pretty clear he wants to stay the course and there must be no drawdown in troop levels for the time being. This chimes with Bush's reasoning and the Republican presidential contender John McCain is also onside, calling Petraeus "one of the great generals in American history". But what if Clinton or Barack Obama gets into the White House? What happens if one or the other makes good their party's wish to initiate a withdrawal plan within 60 days of getting into office?

Showing the diplomacy for which he is noted, Petraeus has hedged his bets, telling friends that generals take orders from the commander-in-chief, but the odds are that he would put up a fight before making any concessions.

It would go against the grain to give up at the very point he believes he is making sufficient ground, militarily and politically, to win this bitter and long-lasting insurgency war.

He is known to be a great admirer of Field Marshal Sir Gerald Templar, who was largely responsible for winning the insurgency war in Malaya (1948-60) and got his way with politicians by insisting: "The shooting side of the business is only 25% of the trouble, the other 75% is getting the people of this country behind us." So we can expect a battle royal on that front.

The other main issue in his bailiwick will be Iran. Already there are some clues. Petraeus has made no secret of the anger he feels about Iranian complicity in the manufacture of the roadside bombs that have killed so many US and coalition soldiers.

Whenever these lethal weapons have been used, he has been quick to blame the Iranian Revolutionary Guards, the organisation that has been fingered by US intelligence as the main culprit for its role in supplying the technology to Shia insurgency groups.

How to deal with it is another matter. Petraeus and Lieutenant-General Ray Odierno, his new man in Iraq, are too cautious to recommend an invasion or even a nuking, but a surgical strike could be on the cards. Just look at what happened in the Syrian desert last September.