On May 2, 2005, Tony Blair's government will begin its ninth year of running the United Kingdom. That tenure makes Blair the nation's longest-sitting Labour leader in the history of his party, and one of the longest of any party in the modern history of the nation. Indeed, Blair, who turns 52 on May 6, is the longest-sitting leader of a leftist party of any sizable Western nation today (German Chancellor Gerhard Schröder, a Social Democrat also still in power, came to office a year after Blair). For any leader even nominally on the left, such longevity is a remarkable accomplishment. Yet Blair is vilified by much of the U.K. left, and if his legacy were written today, he would be remembered primarily for one policy, which was anticipated by absolutely no one when Labour was elected in 1997: his support for George W. Bush's war in Iraq. Blair's embrace of the war and subsequent occupation is conspicuous in part because it goes against Labour's once-reflexive pacifism; Prime Minister Harold...