The W. Stands for Wilson: Friedman is inclined to forgive Bush for what may be the biggest flip-flop of all: campaigning against nation-building, then making nation-building in the Mideast the cornerstone of his foreign policy.

Woodrow Wilson went through a similar transformation, notes Mr. Sandel. He campaigned for re-election in 1916 boasting of having kept the country out of Europe's messy war. But by April 2, 1917, Mr. Wilson was standing before a joint session of Congress, seeking a declaration of war against Germany and insisting that the world "must be made safe for democracy."

Likewise:

This happened to Lincoln during the Civil War. At the outset, the purpose of the Civil War for Lincoln was to oppose secession and preserve the Union . . . In Lincoln's case the rationale for the war shifted, not because he couldn't find any W.M.D. in Dixie, but rather, argues Mr. Sandel, "because of the enormity of the sacrifice that the war was requiring. It no longer made moral sense that this great sacrifice could just be about keeping these states together, could just be about a political structure. It had to be about a bigger purpose and that was freedom and equality."

That leaves the question open, however, as to the wisdom of the Bush doctrine. If Lincoln and Wilson prove anything, they prove that the virtue of one's goals doen't automaticvally dictate success. In one kind of success, Lincoln's rationale for fighting settled the slavery conflict in the context of a war over the frangibility of the union; resentment burned in the South for years, though, and some of Lincoln's means for both ends are open to justified critique. The Wilson Doctrine, on the other hand, went nowhere. Rebuffed by much of Europe, then spurned by Congress, Wilson's idealistic interventionism became, like Wilson himself soon thereafter, a dead letter. I'm not much of a historian, but there are lessons for today in both comparisons, and for both Bush and his opponents.