Potential Republican candidates disagreed over foreign policy and other security issues on Saturday [GALLO/GETTY]
Republican presidential hopefuls have debated their plans for the security and foreign policies of the US, this time going head to head in the town of Spartanburg, South Carolina.
The issue-driven debate on Saturday was a departure from a Republican campaign that has largely been about criticising Barack Obama on the weak US economy and rising joblessness. This time they attacked the sitting president for his position on Iran and its alleged pursuit of nuclear weapons.
"If we re-elect Barack Obama, Iran will have a nuclear weapon," Mitt Romney, the former Massachusetts governor, said during the debate.
On Afghanistan, Jon Huntsman, the former governor of Utah, and Ron Paul, congressman from Texas, both said it was time for US troops to come home after a decade of war.
Michele Bachmann, congresswoman from Minnesota, said that Iran's alleged attempt to develop a nuclear weapon is part of a regional push against Israel.
She said Iran is working with Syria and groups like Hamas to push its agenda.
"The table is being set for worldwide nuclear war against Israel," Bachmann said.
Romney, running a steady, it's-all-about-the-economy campaign, has been at or near the top of the public-opinion polls for months. A succession of rivals vying to emerge as his principal challenger has risen and fallen in turn.
The latest soundings show Herman Cain as the current leader, although Newt Gingrich, the former House of Representatives speaker, has risen significantly in national polls in recent weeks as Rick Perry, the Texas governor, has fallen back.
While the subject matter of defence and foreign policy did not lend itself to a major discussion of the principal campaign controversies, the race has had plenty of them in the past two weeks.
Cain has denied charges of sexual harassment after four women levelled accusations, while Perry embarked on an apology tour after failing in a debate on Wednesday night to remember the name of the third of three cabinet-level departments he wants to abolish.
Bachmann, Huntsman, Paul, and Rick Santorum, a former senator, have all been contending among the second-tier candidates, trailing the evolving group of leaders.
Any attempts to score points off a rival at the debate lacked the personal antagonism of earlier encounters. The tone was set at the outset, when the Republicans were asked if they would support a pre-emptive strike to prevent Iran from acquiring a nuclear weapon.
Gingrich quickly agreed with Romney, saying that if all other steps failed, "You have to take whatever steps are necessary" to prevent Iran from gaining a nuclear weapon.
Santorum agreed, noting that a mysterious computer virus had caused disruption inside Iran's nuclear labs, and that Iranian scientists have been killed in recent months. He said "I hope that the US has been involved" in those and other covert actions.
Paul wanted no part of a military strike. "It's not worthwhile to go to war," he said.
He said that if US security is threatened, the president must ask congress for a formal declaration of war before taking military action.
Perry responded without answering the question. "This country can sanction the Iranian central bank right now and shut down that country's economy, and that's what the president needs to do," he said.
The US has long had sanctions in place against Iran, and Obama made remarks on Saturday suggesting there will soon be more.