Why Is Rudy Smiling?

Yes, the political rule book says a pro-choice former New York City mayor married to wife No. 3 cannot possibly win the Republican presidential nomination — not as long as the G.O.P. remains the preferred party of small towns and social conservatives.

However, the political rule book has been stuffed into a shredder this year. Come summer of 2008, one or both parties will likely fire it from a confetti gun. A million fluttery pieces of conventional wisdom will swirl around a nominee or nominees once thought to be impossible: a woman, a black man, a guy in...