The much-awaited Pennsylvania Democratic primary is at hand, and the day could be a turning point in the 2008 presidential campaign. Senator Clinton could be knocked out of the race altogether by a surprise Obama win (or even by a very strong second-place showing). More likely is a comfortable but not decisive Clinton win, which will probably prolong this battle for the nomination. A blowout for Clinton--unlikely but not impossible--could reshuffle the deck considerably, but barring any unforeseen developments between now and the summer, I think Obama retains the upper hand in this campaign.
