Jonathan Clarke, a senior fellow at the Carnegie Council for Ethics in International Affairs looks back at the rise and fall of the neo-cons, who encouraged George Bush to invade Iraq.
With the Bush administration about to recede into history, a widely asked question is whether the neo-conservative philosophy that underpinned its major foreign policy decisions will likewise vanish from the scene.
The answer seems likely to be yes.
Dick Cheney (Right) was a key ally for the neocons
But the epitaph of neo-conservatism has been written before - prematurely, as it turned out, in the 1980s.
Having been apparently headed for extinction at the end of the Reagan administration a second generation emerged in the mid-1990s.
This was period of post-Cold War overwhelming US military dominance which the neo-cons anointed as the "unipolar moment". It acted as the incubator for the ideas of modern neo-conservatism.
The main characteristics of neo-conservatism are:
- a tendency to see the world in binary good/evil terms
- low tolerance for diplomacy
- readiness to use military force
- emphasis on US unilateral action
- disdain for multilateral organisations
- focus on the Middle East
Prominent neo-cons destined to play a major role in the Bush Administration included Paul Wolfowitz, Douglas Feith, Elliott Abrams, David Addington and Richard Perle.
Neo-con advocates in the media included Bill Kristol and Norman Podhoretz, while in academia, Bernard Lewis and Victor Davis Hanson were among those who provided intellectual heft.
Critics of neo-conservativism have sometimes sought to portray it as an exclusively Jewish phenomenon. But while many of the best-known neo-cons are Jewish, this is incorrect.
Richard Perle, Doug Feith and Paul Wolfowitz held senior positions
In Washington DC, the favourite neo-con think tank was the American Enterprise Institute.
Here they authored a series of papers arguing for a more forceful US foreign policy, the centre-point of which was a rejection of conventional negotiations on the Palestine/Israel peace process.
Instead, they harboured the much bolder ambition of a US-instigated region-wide democratic transformation.
The first phase was the overthrow of Saddam Hussein - which, they believed, would have a sort of "demonstrator effect" on the region.
At the beginning of the Bush administration, the neo-cons' prospects looked dim.
True, several - like Wolfowitz, Feith and Perle - obtained senior appointments, but Bush himself had promised a "humble" foreign policy, the diametric opposite of the neo-con approach.
Neither Secretary of State Colin Powell nor Secretary of Defense Donald Rumsfeld was a neo-con.
The neo-cons did, however, find a crucial ally in Vice-President Dick Cheney.
Although not one himself, Mr Cheney was a founding signatory of the Project for the New American Century, which became the preferred forum for neo-con thinking.
A critical crossover point with the neo-cons was Mr Cheney's commitment to the bold deployment of US military power.
His alliance with the neo-cons proved critical for them.
Their opportunity came with the terrorist attacks of 9/11.
More than anyone else they had a well-prepared strategy which matched the need of the day for a bold, decisive response.
No-one else came close to them in having a ready-to-go action plan.
Suddenly, their ideas of democratic transformation looked like a reasonable policy option.
Their proposals to attack Iraq rapidly moved to centre stage.
Clearly, the neo-cons were not the only - or even the main - actors in bringing about the Iraq war.
But the key fact remains it was their ideas that ensured that the US response to 9/11 would go beyond Afghanistan.
They were, without doubt, the intellectual godfathers of the war.
The first few weeks of the war represented the high-water mark for the neo-cons.
On the battlefield, everything seemed to be going their way; politically, their protege Ahmed Chalabi seemed on track to accede to power.
But as invasion turned into occupation and the insurgency intensified, the neo-con ideas of region-wide democratic transformation were revealed for the fantastical pipedreams they always were.
With the Bush administration ratcheting back its definitions of success in Iraq, the neo-cons were in full retreat.
They started to leave the administration, as elite and public opinion shifted decisively against the war.
In many ways, the 2008 election represented a direct repudiation of the neo-con style of foreign policy based on military-centred, unilateralist overreaching.
At first sight, the incoming Obama administration appears to be the polar opposite of neo-conservatism.
Its instincts are multilateralist, being committed, for example, to adhering to the Kyoto Protocol and to international agreements like the Geneva Convention.
It places a high priority on diplomacy, with President-elect Obama being open to direct talks with long-ignored countries like Iran and Cuba. Defense Secretary Gates, who is remaining in office, has made it clear that he regards military intervention as the genuinely last option.
Furthermore, the financial meltdown and the drains of the Iraq and Afghan wars have chipped away at the pre-eminence of US power. It is difficult to argue today that the US enjoys a unipolar advantage.
The safest bet, therefore, is that we can bid adieu to the neo-cons and leave their role to be adjudicated by history.
The flipside of neo-conservatism is neo-humanitarianism - the idea that US military power should be used to intervene on the ground in crises like the Rwandan genocide or in Darfur
They themselves argue that they form part of the mainstream of American history. It seems more likely that they will come to be seen as an aberration.
Two things may change this. First, the flipside of neo-conservatism is what might be called neo-humanitarianism. This is the idea that US military power should be used to intervene on the ground in crises like the Rwandan genocide or in Darfur.
Some Obama officials, for example Susan Rice at the UN, will be making this case. All indications are that the Obama administration will be cautious but, if not, US unilateral military deployment may be back on the global agenda.
Secondly, the Obama administration faces unsettled business on Iran.
The neo-cons are arguing that Iran is the defining issue for US foreign policy and that, short of an abandonment by Tehran of its apparent nuclear weapons program, the US must use force.
Once again, the early signs are that, for the Obama team, military force is well down the agenda and a new form of engagement is under consideration.
Should this change - possibly on the back of intransigence from Tehran - the neo-cons will be back in business and will crow that they have survived yet another premature obituary.
Jonathan Clarke is co-author, with Stefan Halper, of America Alone: The Neo-Conservatives and the Global Order