Fouad Ajami, in the Wall Street Journal, answers liberal recriminations over the war’s origin occasioned by the McClellan book by pointing to results.

Of all that has been written about the play of things in Iraq, nothing that I have seen approximates the truth of what our ambassador to Baghdad, Ryan Crocker, recently said of this war: “In the end, how we leave and what we leave behind will be more important than how we came.”

It is odd, then, that critics have launched a new attack on the origins of the war at precisely the time a new order in Iraq is taking hold. But American liberal opinion is obsessive today. Scott McClellan can’t be accused of strategic thinking, but he has been anointed a peer of Zbigniew Brzezinski and Brent Scowcroft. A witness and a presumed insider – a “Texas loyalist” – has “flipped.”

Mr. McClellan wades into the deep question of whether this war was a war of “necessity” or a war of “choice.” …

Nowadays, we hear many who have never had a kind word to say about the Iraq War pronounce on the retreat of the jihadists. It is as though the Islamists had gone back to their texts and returned with second thoughts about their violent utopia. It is as though the financiers and the “charities” that aided the terror had reconsidered their loyalties and opted out of that sly, cynical trade. Nothing could be further from the truth. If Islamism is on the ropes, if the regimes in the saddle in key Arab states now show greater resolve in taking on the forces of radicalism, no small credit ought to be given to this American project in Iraq.

We should give the “theorists” of terror their due and read them with some discernment. To a man, they have told us that they have been bloodied in Iraq, that they have been surprised by the stoicism of the Americans, by the staying power of the Bush administration.

There is no way of convincing a certain segment of opinion that there are indeed wars of “necessity.” A case can always be made that an aggressor ought to be given what he seeks, that the costs of war are prohibitively high when measured against the murky ways of peace and of daily life.

“Wars are not self-starting,” the noted philosopher Michael Walzer wrote in his seminal book, “Just and Unjust Wars.” “They may ‘break out,’ like an accidental fire, under conditions difficult to analyze and where the attribution of responsibility seems impossible. But usually they are more like arson than accident: war has human agents as well as human victims.”

Fair enough. In the narrow sense of command and power, this war in Iraq is Mr. Bush’s war. But it is an evasion of responsibility to leave this war at his doorstep. This was a war fought with congressional authorization, with the warrant of popular acceptance, and the sanction of United Nations resolutions which called for Iraq’s disarmament. It is the political good fortune (in the world of Democratic Party activists) that Sen. Barack Obama was spared the burden of a vote in the United States Senate to authorize the war. By his telling, he would have us believe that he would have cast a vote against it. But there is no sure way of knowing whether he would have stood up to the wind. …

It is not easy to tell people of threats and dangers they have been spared. The war put on notice regimes and conspirators who had harbored dark thoughts about America and who, in the course of the 1990s, were led to believe that terrible deeds against America would go unpunished. A different lesson was taught in Iraq. Nowadays, the burden of the war, in blood and treasure, is easy to see, while the gains, subtle and real, are harder to demonstrate. Last month, American casualties in Iraq were at their lowest since 2003. The Sunnis also have broken with al Qaeda, and the Shiite-led government has taken the war to the Mahdi Army: Is it any wonder that the critics have returned to the origins of the war?

Five months from now, the American public will vote on this war, in the most dramatic and definitive of ways.