Notable moments from GOP debate in Arizona

Notable moments from the GOP presidential debate Wednesday night in Mesa, Ariz.

SANTORUM UNDER FIRE

Rick Santorum's first debate since surging to the top of polls might be one he'd like to forget. The former Pennsylvania senator took fire from all sides — even from an unsympathetic audience that twice booed him during answers.

Santorum's chief rival for the GOP nomination, Mitt Romney, led the attack. Within moments of the beginning of the debate, the former Massachusetts governor criticized Santorum for votes during his years in Congress to raise the debt ceiling, place earmarks in bills, and provide money for Planned Parenthood and the Education Department.

Romney wasn't alone. Rep. Ron Paul dismissed Santorum's conservative credentials, saying he was a "phony" conservative.

The audience took its shots when Santorum explained why he voted for the No Child Left Behind law, President George W. Bush's signature education plan, and when he tried to talk over Romney during the debate.

Santorum fought back, attacking Romney for the health care plan he crafted as governor and for his support of the Wall Street bailout. But Santorum spent much of the night on the defensive.

BIRTH CONTROL

CNN debate moderator John King pressed the candidates for their views on contraception, a topic that's arisen as a point of contention in the Republican primaries. The candidates — and the audience, which booed King's question — were having none of it, though. They quickly pivoted to attacks on President Barack Obama.

Gingrich said that rather than discuss his own views on contraception he'd rather talk about Obama's support of "infanticide." Romney said Obama's polices on birth control have been an attack on religious tolerance.

Santorum used the discussion to warn about the dangers of out-of-wedlock pregnancies.

Paul, a doctor, says that contraception doesn't lead to immorality, immorality leads to contraception.

IN A WORD

Forget the in-depth plans and white papers that candidates like to brag about. The GOP candidates were asked to describe themselves in a single word. Ron Paul said he is "consistent." Santorum described himself as "courageous." Romney said he is "resolute." There was a bit of laughter in the debate hall when the occasionally dour Gingrich chose his word: "Cheerful."