Romney: Iran will obtain nuclear weapon if Obama is re-elected

The Republicans vying to challenge President Obama in next year's election slammed his administration's foreign policy, suggesting he's bungled efforts to prevent Iran from obtaining a nuclear weapon and played politics with a troop drawdown in Afghanistan.

"If we re-elect Barack Obama, Iran will have a nuclear weapon," Mitt Romney declared in a foreign policy debate in South Carolina sponsored by CBS News and National Journal. "If you elect me as president, Iran will not have a nuclear weapon."

Romney, who described Obama's position on Iran as the president's "greatest failing," said he would use any means necessary, including military action, to prevent Iran from obtaining a nuclear weapon.

Rival Herman Cain stopped short of pledging military action, suggesting he'd fund dissidents challenging the Iranian government instead.

Meanwhile, Newt Gingrich said the positions advocated by Cain and Romney were "superior" to the Obama administration, which he contended had "skipped all the ways to be smart" about Iran, including investment in more covert operations to block and "disrupt" their efforts to obtain a nuclear weapon.

"All of it covertly, all of it deniable," Gingrich added.

The CBS/NJ debate was the first to explicitly focus on foreign policy, an issue that has drawn scant attention on the campaign trail and in recent Republican presidential debates.

One reason foreign policy hasn't gotten much attention is that the field largely agrees on big picture issues, including the need to do more about Iran's pursuit of nuclear weapons. Yet the candidates exhibited strong disagreements on the United States' approach toward Afghanistan and whether the country should be offering foreign aid to Pakistan.

Both Romney and Rick Perry slammed Obama for speeding up a troop drawdown in Afghanistan, suggesting his decision was tied more to the politics of the upcoming election than conditions on the ground.

"To give a time table to our enemy is irresponsible," Perry said.

But Jon Huntsman, who served as President Obama's ambassador to China before leaving his post to run for president, said the troops should come home.

"I say this nation's future is not Afghanistan. This nation's future is not Iraq," Huntsman said, to little applause. "I don't want to be nation building in Afghanistan when this nation needs so desperately to be rebuilt."

The candidates also disagreed on Pakistan, a country that has had an increasingly tense diplomatic relationship with the United States. Perry argued the United States should pull its foreign aid from the country—telling the audience that every country would begin with "zero" foreign aid if he were elected president.

"The foreign aid budget in my administration will start at zero dollars," Perry said. "Zero dollars. And then we'll have a conversation."

But Michele Bachmann and Rick Santorum argued Perry's position was naïve, pointing to the fact that Pakistan has a nuclear weapon that could fall into the wrong hands.

"We must engage them as friends, get over the difficulties that we have," Santorum said.

Meanwhile, Bachmann and Cain both said if they are elected they would approve waterboarding as a way to interrogate potential terrorism suspects.

While the subject of the debate was foreign policy, the larger focus was on Perry, whose campaign has been in crisis mode since Wednesday when he froze during a key moment in the last debate. On Saturday, the Texas governor had a better night and committed no major gaffes, even though foreign policy is not considered one of his stronger points.

At one point, Perry joked about his embarrassing debate flub. Asked by moderator Scott Pelley about the Department of Energy, Perry smiled and interrupted.

"Glad you remembered it," Perry said, as his rivals giggled.

"I've had some time to think about it, sir," the CBS News anchor replied.

"Me, too," Perry said, grinning as the audience broke into laughter and applause.

Still, while the debate was marked by disagreements, none of the candidates took direct aim at Romney. At one point, Gingrich was asked about comments he made on a radio show Friday in which he suggested the former Massachusetts governor lacked the leadership skills to be president.

Asked to explain his comment, Gingrich flatly declared, "No."

He said he'd made the comments because he was on a radio show and insisted a debate forum was not the proper venue in which to attack a fellow candidate.

"We're here tonight to talk to the American people about why every single one of us is better than Barack Obama," Gingrich insisted. "And that's the topic."

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