What happened
The leading Republican presidential candidates traded their sharpest attacks of the campaign on Sunday, taking turns accusing each other of siding with Democrats on abortion, immigration, and other divisive issues. Former senator Fred Thompson, a relative newcomer to the race, set the tone by questioning the conservative credentials of front-runners Mitt Romney and Rudy Giuliani, who responded by saying that Thompson, a lawyer, had “stood with Democrats over and over again” to block tort reform.

What the commentators said
The race is on, said Reid Wilson in RealClearPolitics. “With just over seventy days to go before the first presidential nominating contests, no front-runner was safe, and unlike previous debates, no candidate declined to take shots either.” The gloves really came off when Thompson said that former New York City mayor Giuliani sided with the field’s shared nemesis—Hillary Clinton—on abortion and immigration. Clearly, “the Republican race will only get more heated” after a night like that.

Guiliani took some heat, said Rich Lowry on National Review Online’s The Corner blog, but he was the most impressive—“forceful, lively, substantive.” The evening’s other big winner was Sen. John McCain, who demonstrated “his knowledge of the issues with a nice dose of humor.” Overall, the entire field looked pretty good.

Thompson displayed “a degree of passion unseen in his first debate appearance two weeks ago,” said Jonathan Martin in The Politico. His assault on Giuliani’s support of abortion rights, immigration safe havens, gun control, and his 1994 support for Democratic Gov. Mario Cuomo’s reelection were the “toughest charges” in a night of “fireworks.” Thompson deflected concerns about his “purported laziness” with a convincing list of his accomplishments—from becoming a father at 17 to shepherding John Roberts to confirmation as Supreme Courth chief justice—so he was the one who stole the show.