Mitt Romney

Passed his first high-profile test with aplomb. Showed the sunny-side-up optimism, smoothly relaxed demeanor and mechanically thorough preparation that have won over donors and talk show hosts alike. Never rushed his answers or got flustered. Deftly told a Ted Kennedy joke and closed with a stone cold hit on Hillary Clinton/Harry Reid/Nancy Pelosi. Voters getting their first real look at Romney probably liked what they saw. Still has to explain his shifted positions and return harder foreign policy volleys.

— Mark Halperin