The Iraq war became emblematic of President Bush's faith in traditional American power at a time when new manifestations of power – a country's international standing, its involvement in spreading international development, the attractiveness of its values – have taken on new importance.
"Bush focused so heavily on the hard power that he neglected the soft power," says Harvard Prof. Joseph Nye, describing the availability of nonmilitary means for pursuit of national interests.
Citing a decline of 30 percentage points in European attitudes toward America and an even steeper decline in many Muslim countries, Mr. Nye says such figures are "a good measure of the effect of Iraq on America's attractiveness" and also on its interests. But not everyone agrees with this interpretation.
Some historians and foreign-policy experts note that the Iraq war was not a "go-it-alone" affair. They also tend to hold out the prospect – as does Mr. Bush himself – that a stable, democratic Iraq will emerge, becoming a "beacon" for the region and vindicating Bush's vision.
"The truth is that about two-thirds of the governments of NATO and the European Union supported Bush in his fateful decision to go to war in Iraq," says Robert Lieber, a professor of government and international affairs at Georgetown University in Washington. "This idea that the Bush administration ... ruined relations with our allies is a cliché and also happens to be wrong."
Iraq's place in Bush's foreign-policy legacy cannot be fully gauged, some say, without including his decision to address a deterioration in conditions on the ground with a "surge" in US troops, rather than with a withdrawal.
"Iraq would be in very different shape today if Bush's presidency had ended a year-and-a-half ago and [America] had followed the prevailing thinking" to pull out, says Michael Gerson, a former Bush speechwriter. "Instead the surge has delivered some of the most remarkable progress in counterinsurgency we have ever seen."
Still, Mr. Lieber says, there's no denying the war's high costs – from loss of life to the hit to America's reputation caused by poor prewar planning and the ineptness of Iraq's new government.
But the most negative cost may be in how the war "freed Iran to become the dominant actor in the region," Lieber says. That consequence, he warns, "is fraught with peril."