If you like to read the odd alternative history book, then consider this possibility: Rudy Giuliani may have the person most responsible for John McCain winning the Republican nomination this year.
Let me explain.
Giuliani was the leader in the polls of Republicans nationally throughout much of 2007. Somewhere along the way he decided that he didn't have much hope of doing anything in Iowa, so he stayed away from that state's caucus.
But after several visits to New Hampshire, he made the same decision's about that state's primary. Now let's think about that.
New Hampshire would seem to be tailor made for Giuliani. He's on the liberal side as Republicans go -- there's an understatement -- and figured to have more appeal to independents than many Republican candidates. And, what do you know, New Hampshire has an open primary. Independents can show up and vote for either party, and they did.
So, Giuliani decided to drop out and head to Florida. McCain went on to win the New Hampshire primary over Mitt Romney, in part because he received a good-sized share of the independent vote. Suddenly, McCain had some momentum -- the "Mac is back" slogan carried him through South Carolina and then through Florida, where Giuliani was making his first and last stand.
If Giuliani had hung around for New Hampshire, he might have cut into McCain's total -- perhaps enough to throw the primary to Romney. That certainly would have given the process an entirely different dynamic. It wouldn't have helped Giuliani, but we may have had a different eventual nominee ... and perhaps a different President.