Rudy Giuliani

Stood up to onslaught from Thompson on his immigration position, and uncharacteristically chose to fight back rather than dodge. Spent most of his time dispensing calm quips and New York statistics, and played the Clinton card whenever he could. Like the other leading candidates, had a few stumbling moments (like on gay rights) and some high-flying rhetoric, but mostly was just fine — and fine is good enough when you're the frontrunner.

—by Mark Halperin