But Campbell, a Pentagon official in the Clinton administration and now head of the Centre for a New American Security, a Washington think tank, wanted to explain that these metaphors did not quite capture the true nature of the neocon. A silver bullet in the heart could kill a vampire, but not a neocon; and werewolves went crazy at night, but a neocon did crazy things at any time, Campbell joked to much laughter, reported Steve Clemons of the New America Foundation in his blog, The Washington Note.

Campbell continued that "a better analogy was 'intellectual special forces' - highly trained, confident, ninja-like, working well in small teams but always seeking to define the terrain of conflict. They will not stand and fight if things go poorly but instead will search for a better battle." The problem was that a leading neocon was at the same dinner. Robert Kagan was not amused. He decided to protest. The Americans were in London for a conference the next day. Kagan, who had been invited as a speaker, decided to boycott the conference so he could avoid sharing the stage with Campbell. A rueful Campbell went shopping to buy Kagan a tie and wrote him a note of apology, says Clemons. Here is the irony. Kagan is a card-carrying neocon. He was a co-founder of the main neocon vehicle for pressing for the invasion of Iraq, the Project for the New American Century. Through this he shares responsibility for that disastrous misadventure.

Yet it was not Kagan writing the apology. It was Campbell, a member of the "realist" school of foreign policy and not an advocate of the invasion, while Kagan struck an indignant pose. Elsewhere, Campbell had marvelled at this phenomenon - the insouciance of people he calls Iraqitects: "Perhaps part of the curiosity is because this current generation of war planners has conducted themselves so much differently than the Vietnam era Masters of the Universe," he wrote in The New York Times in November. "Many from the version 1.0 of the best and the brightest - those intrepid Cold Warriors who led the country to a slogging defeat in Vietnam - had to subsequently endure booing on college campuses, shunning from old friends and colleagues, brutal treatment from the commentariat of the time, and the kind of bitter despair that generally accompanies a thoroughgoing battlefield defeat.

"The version 2.0 era of neoconservative advocates of military action to topple Saddam have behaved very differently in the midst of our current quagmire in Iraq. Almost all have generally tried to put on a brave public face and to remain on the intellectual offensive, pointing out the weaknesses and limitations of their critics and full of ideas for what the US can do next in the world. Even after offering atrocious advice to President Bush during the 2000 campaign, most of them are back again." And they have indeed found their "better battle". The neocons are now agitating nonstop in the campaign to attack Iran. But weren't the neocons in the Bush Administration all purged?

Men like the deputy secretary of defence, Paul Wolfowitz, and the undersecretary of defence for policy, Doug Feith, were forced out. So was the former US ambassador to the UN, John Bolton, and the chief of staff to the Vice-President, Lewis "Scooter" Libby. With no neocons in government, surely their only attacks now have to be rhetorical - surely they cannot wage war. But a number of key neocons have arrived in the inner circle of the candidate to become the next Republican president, John McCain.

This is being taken very seriously by American foreign policymakers. "There's no doubt that some neocons like Senator Joe Lieberman are linked to McCain at the elbow like Siamese twins," said one of the grey eminences of US foreign policy, Zbigniew Brzezinski, national security adviser to Jimmy Carter and now an adviser to the Democrats' presidential candidate, Barack Obama. "Lieberman believes that we are already in World War Four and his complaint is that we are not sufficiently conscious of it or sufficiently belligerent," Brzezinski told the Herald. On Iran, Lieberman advocates air strikes to disable its nuclear program. Other notable neocons who are now counted as McCain advisers are Bolton; William Kristol, the editor of the neoconservative journal The Weekly Standard and son of the neocon intellectual founder, Irving Kristol; a former Wolfowitz ally at the Bush Pentagon, Peter Rodman, and the easily offended Robert Kagan.

Crucially, a neocon has landed as chief co-ordinator of McCain's foreign policy and national security teams. Randy Scheunemann was the founder of the Committee for the Liberation of Iraq and, like Kagan, was one of the founders of the Project for the New American Century. This clustering of neocons around a possible next president troubles American analysts for two principal reasons.

First, the neocons' record lends them no credibility, yet their positioning around the candidate gives them enormous potential power. The neocons were adamant about the need to invade Iraq. Kristol and Kagan wrote in 2001: "The road that leads to real security and peace is the road that runs through Baghdad." They were wrong. The invasion destabilised Iraq and unleashed a civil war between the Sunnis and Shiites whose future remains completely unpredictable. The invasion empowered Iran. It energised terrorists around the world. It compromised US power. It sent the US to its lowest point in world regard since Vietnam. It needlessly killed hundreds of thousands of innocent Iraqi civilians and 4000 US troops to date. Its ultimate financial cost will be counted in the trillions of dollars. It reduced Iraq's oil output. And yet the neocons, in general, remain unbowed and unrepentant. Second, the neocons' world view is ideological; zealotry is a poor guide for cool-headed and judicious policy-making. The neocon, unlike the realist, is an idealist and believes in a revolutionary doctrine. He believes that America's unique mission is to civilise the world at gunpoint.

Professor Andrew Bacevich, of Boston University, says there are five defining characteristics of neoconservatism. The neocon believes that: * US global domination is benign and other nations see it as such;

* Any lapse in US domination will create chaos; * Military force is necessary to impose democracy; * US military power must always be expanded to allow it to intervene decisively in every critical region of the world simultaneously if necessary; and

* Realists in foreign policy must be aggressively targeted and defeated. As Bacevich puts it, the neocon cannot abide the realist because "realism was about defending national interests, not transforming the global order".

So it has been much remarked in Washington that McCain's advisory group contains not only some of America's leading neocons, but also some of its famous realists. Asked about the influence of neocons in McCain's campaign, his lead Asia adviser, Mike Green, points to this fact: "If you look at McCain's senior group, it includes Henry Kissinger and George Shultz and Bob Zoellick - it's hardly a pantheon of neocons. "And the advisory group, at the next level down, includes moderate conservatives like me," said the former senior director for Asia in the Bush White House. "I have never felt I've needed to butt heads with neocons. "But John McCain has been involved in national security for decades. The idea that he could be taken over by any adviser is totally mistaken. On almost everything, McCain already has a stated position."

And his stated position on Iran? "You mean a serious position, or him singing 'Bomb Iran'?" asks Green, referring to the infamous YouTube clip of McCain during a public appearance singing those two words over and over to the tune of the Beach Boys tune Barbara Anne. Asked for the longer version of the candidate's position, Green says: "Barack Obama's pledge to meet personally with the leadership of Iran is definitely not where McCain is. He's been one of the leading people in the Senate arguing that Iran is the leading threat to Iraq, arguing that Iran is on the offensive in Gaza and Lebanon and efforts of diplomacy and offers of carrots have been rebuffed by the regime.

"You have France, Germany and Britain arguing we need more pressure on Iran - that's pretty much where McCain is. He is sceptical of what you can get through talking. The more important thing is to put more pressure on them." Green portrays this as a practical middle way of approaching Tehran: "There is more to Iran policy than bombing them or talking to them." Steve Clemons of the New America Foundation explains that he is anxious about the neocons' Iran policy "because they regard the mullahs of Iran as the greatest threat to Western values, and many of them also worry about Israel. When you take these concerns and then consider Iran with nukes, the neocons just go crazy."

But the simple answer is not necessarily to vote Democrat: "I worry that Barack Obama worries that he won't be trusted by the American people on national security and he may be looking for an action to define himself. So Obama could end up looking a lot like a neocon." It is easy to make fun of the neocons, but Washington is alive with the concern that they may yet have the last laugh.