For the tiny slice of the American public that cares whether neoconservatives stand as one or are, to a degree, divided on the war in Iraq and its effects, the recent disagreement between neocons Charles Krauthammer and Francis Fukuyama is hot dinner-party conversation. For the other 99 percent of us, it is a fine example of a vital and engaged political philosophy.

Agree or not with this branch of conservatism broadly defined as promoting an aggressive foreign policy and a belief in the universality of democracy, the fact it is vigorously debating and occasionally refining its positions is a sign of health. To the extent neocons can tolerate gleeful opponents celebrating an apparent rift, they’ll be a stronger movement.

The current issue is the view of Mr. Krauthammer, a columnist for The Washington Post, of the U.S. role in the world, post-Cold War. Among his conclusions is this policy axiom: “We will support democracy everywhere, but we will commit blood and treasure only in places where there is strategic necessity – meaning, places central to the larger war again the existential enemy, the enemy that poses a global mortal threat to freedom.”

In a recent edition of The National Interest, Mr. Fukuyama, author of “The End of History,” responds, “If these words have any real meaning then they should include only those threats to our existence as a nation or as a democratic regime.” Mr. Fukuyama is rethinking his earlier support for the war in Iraq, which is irritating fellow neocons and has chosen a passage that does sound something like the vague Democratic murmurings of “national interest” of a dozen years ago.

In any event, Mr. Krauthammer is having none of it. In a recent New York Times story, he said the criticism was “breathtakingly incoherent,” which is how think-tank types talk among themselves even when they are friends.

For Democrats happy to see any sort of split among neocons, they might recall their own battles in the late 1980s at the Democratic Leadership Council, when a new, more moderate strategy emerged and the party elected and re-elected a president. Not everyone needs to get along all the time in politics. Sometimes, it’s better if they don’t.