It's a good thing for Rudy Giuliani that he believes in the power of optimism. These days his campaign needs some. For most of 2007 the former New York City mayor led the Republican field in national polls, some state polls, and money raised from individual contributors. He appeared to have convinced at least some conservatives that his opinions on abortion rights (he's for them) and gun control (he supports "reasonable restrictions") were less important than his tough stance against terrorism, his unabashed support for supply-side economics, and his promise to appoint what he called "strict constructionist" judges to the federal bench. Poll after poll showed that Republicans believed Giuliani was the GOP's best chance to hold the White House in 2008.

Those days are over. In about eight weeks Giuliani has gone from frontrunner to second-tier candidate. He lost Iowa and New Hampshire, finishing nowhere close to first. His campaign is pulling resources from this week's contests in Michigan, South Carolina, and Nevada to focus on the January 29 Florida primary, where polls still show him in the lead (by a shrinking margin). The news late last week that senior staff are working without pay put the Giuliani campaign on the defensive, causing it to release cash-on-hand figures showing it isn't broke. On the campaign trail, Giuliani is asked most often about his campaign strategy of not seriously competing in all the contested primaries and caucuses before Florida, then using the momentum from winning that contest to do well in large

What explains Giuliani's slide into irrelevance? Fred Siegel, author of a Giuliani biography and an editor at City Journal, says the former mayor's fate is largely out of his control: "Rudy got caught in a windshear--the fall of Hillary, and the rise of Huckabee and McCain." In this view, Hillary Clinton's missteps in the Democratic race removed the chief rationale for Giuliani's candidacy--that he was the best candidate to face down the Clinton machine. Clinton was also Giuliani's chief foil on the campaign trail, providing the mayor with an opponent against whom he could rally Republicans who might otherwise have been wary of the thrice-married New Yorker. Meanwhile, the success of the surge policy in Iraq revived John McCain's candidacy, drawing national security hawks away from Giuliani. And Mike Huckabee's appearance on the national stage provided social conservatives with a likable champion on the issues they think are most important.

Yet the "windshear" doesn't account for the horrible spate of publicity for Giuliani beginning in mid-November--after which publicity the Giuliani campaign began to tank. The indictment of former New York City police commissioner and Giuliani protégé Bernard Kerik on corruption charges, and a report in the Politico that the mayor's office may have paid improperly for trips Giuliani took to visit then-girlfriend Judith Nathan in the Hamptons, forced the mayor into a defensive crouch. While the Kerik story has subsided and an investigation by the New York Times showed the mayor's office paid for the Hamptons trips properly, Giuliani was unable to recover before the Iowa caucuses.