Republican showdown

Contenders for the 2008 Republican and Democratic presidential nominations will be in New Hampshire early next week for separate party debates on June 3 (Democrats) and June 5 (Republicans) -- but the Republican clash is the one worth watching. Unlike the leading Democrats, Republican front-runners Rudolph Giuliani, John McCain and Mitt Romney have enjoyed shockingly substantive exchanges on hot-button issues such as abortion, illegal immigration and torturing terrorists.

Moreover, all three men have serious electoral vulnerabilities with Republican voters, who distrust their social liberalism (Giuliani), chronic flip-flopping (Romney) and suspicious willingness to work with Democrats (McCain). Their exchanges seem to be moving the polls: a May 11-13 Gallup survey gave Giuliani a 6-point lead over McCain, down from 13-24 points earlier in the year. Expect this gap to narrow again after the debate.