Candidates raised the specter of terrorists striking U.S. cities with nuclear bombs as they sought to gain an edge, with Pakistan emerging once again as a key source of disagreement among the White House hopefuls.
"To write a check to countries that are clearly not representing American interest is nonsensical," he said, drawing a sharp rebuke from Rep. Michele Bachmann of Minnesota.
"With all due respect to the governor, I think that's highly naive," she said. "We have to recognize what's happening on the ground. [There] are nuclear weapons all across this nation, and potentially Al Qaeda could get ahold of these weapons. These weapons could find their way out of — out of Pakistan into New York City or into Washington, D.C., and a nuclear weapon could be set off in this city. That's how serious this is."
Perry, who replaced Bachmann as a conservative favorite in the race only to be superseded by Herman Cain and former House Speaker Newt Gingrich, countered that he had never argued for disengaging with Pakistan.
The Obama administration’s plan for a gradual pullout of U.S. troops from neighboring Afghanistan was another point of focus in the Washington debate co-sponsored by CNN and two conservative think tanks, the Heritage Foundation and the American Enterprise Institute.
Former Utah Gov. Jon Huntsman Jr., who has struggled to break out of the bottom tier in the GOP race after serving as President Obama’s ambassador to China, argued that using 100,000 troops for "nation-building in Afghanistan" was not serving U.S. interests.
"We need an honest conversation in this country about the sacrifices that have been made over nearly 10 years," he said.
"We have dismantled the Taliban. We've run them out of Kabul. … We've killed Osama bin Laden. We've upended, dismantled Al Qaeda," he continued, adding that the U.S. hadn't done a good job "defining and articulating what the end point is in Afghanistan."
"I think the American people are getting very tired about where we find ourselves today," Huntsman said.
"Are you suggesting, governor, that we just take all our troops out next week, or what's your proposal?" Romney interjected.
"Did you hear what I just said?" Huntsman snapped back, saying he favored drawing down the number of troops to a force of 10,000 or 15,000 tasked mainly with intelligence gathering and special-forces response capabilities.
Romney said he would defer to commanders on the ground, who have said that the U.S. force in Afghanistan should reduced to 10,000 by the end of 2014. Any move to pull out troops before then, he said, would "put at risk the extraordinary investment of treasure and blood which has been sacrificed by the American military."
"I stand with the commanders in this regard and have no information that suggests that pulling our troops out faster than that would do anything but put at great peril the extraordinary sacrifice that's been made," Romney said. "This is not time for America to cut and run."
Huntsman, in turn, suggested the president should make independent judgments based on more than the advice of military advisors.
"At the end of the day, the president of the United States is commander in chief," he said. "Of course you're going to listen to the generals. But I also remember when people listened to the generals in 1967, and we heard a certain course of action in Southeast Asia didn't serve our interests very well."
Former House Speaker Newt Gingrich clashed with Rep. Ron Paul of Texas over renewal of the Patriot Act domestic surveillance law.
"I’d look at strengthening it," said Gingrich, who argued that nuclear terrorism suspects should not be presumed innocent until proven guilty.
Paul said the Patriot Act was "unpatriotic because it undermines our liberty." He invoked the criminal prosecution of Timothy McVeigh, convicted and put to death in the 1995 bombing of a federal office building in Oklahoma City.
"You can still provide security without sacrificing our Bill of Rights," Paul said.
"Timothy McVeigh succeeded," Gingrich responded. "That’s the whole point."
Paul also differed over civil rights with Rick Santorum, who called the Patriot Act a necessary step when America is at war with terrorists. The former Pennsylvania senator also advocated ethnic profiling by the government, recalling that in the Civil War, "Abraham Lincoln ran right over civil rights."
Asked by CNN anchor Wolf Blitzer what groups should be profiled for security purposes, Santorum said, "Obviously Muslims would be someone you’d look at."
Paul denounced the "careless" use of the word "war," noting that Congress had not declared war and arguing that the civil liberties of terrorism suspects should not be compromised.