It's a good question and while I do not agree with everything in this essay by Austin W. Bramwell, there's meat on its bones. Money quote:
After 9/11, neoconservatives championed any war that we waged in reaction. In this, they were acting opportunistically but not hypocritically: in their view, 9/11 is what happens when the United States suffers any challenges to its authority. The rest of the movement knew only that it wanted a ruthless response. Neoconservatism just happened to provide a convenient ideological infrastructure with which to justify metonymic revenge against some Muslim Arab or other. Before 9/11, the movement was praising modesty in foreign affairs; after 9/11, it did not so much embrace neoconservatism as blunder into it by accident...
What they need is analysis: the skeptical tradition extending from Machiavelli to Hobbes, Hamilton, and Burnham that seeks to understand the world as it is rather than as we might like it to be.
Sound familiar? Bramwell wisely decides that the "conservative movement" is now dead. Conservatism as a philosophy and as a tradition is not, however, dead. How the one comes to reconcile with the other is the question now before us.