“For the first time,” a friend commented recently, “I can understand what the 1930s were about. The people I talk with want to know only one thing: Which side are you on?” Denunciation across the Blue/Red divide, he went on, has replaced any semblance of reasoned argument. In that context, it’s a pleasure to turn to “A Matter of Principle: Humanitarian Arguments for War in Iraq” (University of California Press, 359 pages, $21.95), edited by Thomas Cushman.

The contributors, who include Christopher Hitchens, Adam Michnik, Paul Berman, and John Lloyd, share what Mitchell Cohen of Dissent magazine describes in his chapter as “concurring opinions.” They welcome the United States’s success in bringing down the Iraqi Baathists, but their justifications for the war are rooted in a moral and internationalist case against bloody regimes.

In his introduction, Mr. Cushman, the editor of the Journal of Human Rights, acknowledges the complexity of an issue in which peace and stability were on one side and justice and human rights on the other. Writing in the tradition of 1930s anti-totalitarianism, he tries to lay out a position that is neither morally obtuse realism nor purblind pacifism. The issue, he argues, is not President Bush’s motives but the consequences of allowing Saddam Hussein to stay in power.

Any book written on Iraq runs the risk of being outdated by the time it appears. “A Matter of Principle” was written before both the Iraqi elections and the recent disclosures about Saddam’s use of oil-for-food money to buy Western support. But it remains timely because it is as much about the closing of the liberal mind as it is about Iraq.

Many of the authors, Mr. Cushman notes, have become “intellectual outcasts, banished, scorned and vilified among their fellow liberals for expressing their heterodox views.” They have found that there is “resistance (both) to even hearing the humanitarian case for the war” and acknowledging the reality of popular hostility to Saddam among the Iraqi people. A measure of Mr. Cushman’s open-mindedness is that, once it became clear there were no weapons of mass destruction in Iraq, one contributor, Jeffrey Herf, was allowed to attach an addendum to his article reversing his earlier support for the war.

Speaking to his fellow liberals at Human Rights Watch, Mr. Cushman argues that “any moral critique of the war or the Bush administration must be accompanied by a similar critique of the failure of moral responsibility by the United Nations,” which makes no distinctions between liberal democracies and thuggish regimes of various varieties. Worse yet, he notes, the United Nations has become a forum where the tyrannies of the world can form power blocs and alliances to “use international law to promote and protect their own power.”

Some of this volume’s most interesting essays pick up the question of why the war’s left-wing opponents were so reluctant to cast a critical eye on the motives of France, Germany, and Russia (they might have added Canada). Writing about Germany, Richard Herzinger addresses Chancellor Schroeder’s comment that the postwar period is now completely over to show how both politicians and the public used the tensions between Europe and the United States over Iraq to argue “war could bring nothing but horror and destruction.”

This was a reversal of the position taken a few years earlier, after the Srebrenica massacre. At that time the idea of “never again war” was balanced with the idea of “never again Auschwitz.” But in a “normalized” Germany, anti-Americanism was redefined as the new left-wing version of 1930s-style anti-fascism, in which (to paraphrase Orwell) leftists were anti-American without being anti-Saddam or anti-Islamist.

In France, Michael Taubman sees similar echoes of the 1930s, when the socialists, with the exception of a small minority around Leon Blum, rejected the “imperialism” of both England and Germany. In the new version of moral equivalence, the Americans are no better than the tyrannical regimes of the Middle East.

Bin Laden was presented in the German press, for instance, as a sort of Islamic Robin Hood fighting the “hyperpower” with the only weapons at his disposal. The socialists had never demonstrated against Saddam and his brutalities, but demonstrators were only too happy post-1989 to go into the streets against the United States and revive the 1930s line about how “capitalism brings war just as clouds bring thunder.”

Since this book was completed, the Iraqi election results have underscored the wisdom of Mr. Cushman’s comments about the importance of Iraqi public opinion. But, just as important, it has become clear that oil was a major issue not only for the United States but for Canada and France, where the ruling parties were deeply corrupt and deeply intertwined with companies invested in Saddam’s Iraq.

Mr. Cushman’s book deserves a wide circulation. But I suspect that, like an earlier volume with a similar viewpoint, “The Fight Is for Democracy,” edited by George Packer, “A Matter of Principle” will be ignored in the left-liberal precincts where it could do the most to reopen debate. As in the 1930s, conventional liberals have been drawn into the worldview of the radicals who, whatever their tendencies to obscurantism, seem to have the passion that comes with certainty on their side.

If a decent left is to reconstitute itself, it will need the writers in this collection – people who have both the ardor of their liberal convictions and a hard-nosed take on reality.

Mr. Siegel is the author of “The Prince of the City: Giuliani, New York and the Genius of American Life” (Encounter).