Hillary Clinton

Performed much better than last time, but has lost her luster and ability to consistently rise above her rivals — in part because she course-changed by going a bit ugly and a bit low. She deliberately risked appearing shrill, political and shameless in order to put her opponents in their place — and the chattering class may applaud her steely toughness. For the first time in a debate, she initiated off-topic attacks, forcefully challenging Obama on his health care plan and Edwards for going negative; she knocked both off balance, raising the question of whether they can take a general election punch. Was equivocal on trade issues and Social Security, but not in a sound bite-able way that might come back to haunt her. She may not have her game back, but she's slowed — and maybe stopped — the two-week-old "she's slipping" storyline.

—By Mark Halperin