WASHINGTON — The Republican presidential candidates placed in sharp relief on Tuesday night their party's lack of a single national security vision a decade after the Sept. 11 attacks, differing over the pace of withdrawal from Afghanistan, aid to Pakistan and what to do with illegal immigrants already in the U.S.
In a debate that went deep into foreign policy issues but did little to alter the basic contours of the battle for the Republican presidential nomination, the candidates by and large struck a hawkish tone in dealing with Iran and protecting the U.S. from terrorist attacks.
But under questioning from Wolf Blitzer of CNN and an array of conservative and neoconservative officials from past administrations now affiliated with the other sponsors — the American Enterprise Institute and the Heritage Foundation — the candidates engaged in a number of spirited debates among themselves.
Newt Gingrich, newly resurgent in polls, said he would support an Israeli strike against Iran, if "only as a last recourse and only as a step toward replacing the regime."
Herman Cain, the former Godfather's Pizza chief executive, went one further, saying he would go so far as to help the Israelis in an attack on Iran, though only if "it was clear what the mission was and it was clear what the definition of victory was."
Mitt Romney said he would "stand up to Iran with crippling sanctions."
Gov. Rick Perry of Texas said he would impose a no-fly zone on Syria, and suggested that even Mexico was acting as a staging ground for terrorist groups.
But, channeling Hillary Rodham Clinton's chastisement of Barack Obama in debates four years ago, Rep. Michele Bachmann of Minnesota called former Sen. Rick Santorum of Pennsylvania "naive" for suggesting cutting off American aid to Pakistan, calling it "too nuclear to fail."
Rep. Ron Paul of Texas chastised his Republican opponents for backing a tougher version of the Patriot Act to find terrorists, for taking a hard line on Iran, and for supporting the idea of using racial profiling to single out terrorism suspects, specifically Muslims — criticism that was echoed by former Gov. Jon M. Huntsman Jr. of Utah.
Huntsman, a former ambassador to China, got into one of the sharpest exchanges of the evening with Romney, whom he is hoping to upset in New Hampshire despite his relative low standing in polls. Huntsman repeated his call for most U.S. troops to leave Afghanistan quickly, while Romney is insistent that troops should stay longer than Obama has decreed.
"We don't need 100,000 troops," Huntsman said, clearly reveling in having a substantive back and forth with the front runner.
"This is not time for America to cut and run," Romney snapped.
The debate highlighted more than merely the differences in the foreign policy views of the eight presidential candidates.
The conversation also drew attention to a significant transition inside the party, with old Republican arguments on fresh display in a new world of debt-conscious Washington.
It was one of the livelier debates of in the Republican campaign. The candidates fielded questions not from ordinary voters, but from audience members who included luminaries in previous Republican administrations, including Edwin Meese, who served as attorney general under Ronald Reagan; Paul Wolfowitz, a leading architect of the Iraq war under George W. Bush; and David Addington, a top aide to former Vice President Dick Cheney.
The rise of the tea party has brought new attention to the nation's debt — even in areas of national security that had been treated as sacrosanct over the last decade during the wars in Iraq and Afghanistan.
The candidates showed their differences on the potential cuts to the military that inched closer to a reality this week after a congressional committee failed to find $1.2 trillion in deficit reductions, which could mean $500 billion in reductions to the Pentagon budget over the next 10 years.
While Romney declared that such cuts would be draconian — he blamed Obama for failing to take a leadership role — Gingrich said he would not shy away from finding efficiencies in military spending.
"There are some things you can do in defense that are less expensive," Gingrich said.
The debate often lurched from topic to topic to hot spots around the globe. Not all of the candidates were given the same questions, so it was difficult to size up the differences on key issues. Yet if the debate was a tryout to be the commander in chief, the Republican candidates showed that their degrees of sophistication and preparedness vary widely.
An intense and lengthy discussion broke out over immigration, a flashpoint among Republican voters, as Gingrich said he supported finding a way to allow people living in the country illegally to stay in the U.S.
"I'm prepared to take the heat to say let's be humane to enforce the law," Gingrich said.