When it comes to combating terrorism, the Republican presidential candidates topped the Democrats in using their first 2008 campaign debates to show a willingness to use military force.

Compared with the tone at the Democratic gathering in South Carolina two weeks ago, the Republicans sounded almost trigger-happy in their session in California last week. In dealing with a possible nuclear threat from Iran, for instance, the GOP hopefuls nearly tripped over one other to come across as tough guys. Both of the top two, former Mayor Rudolph Giuliani of New York and Sen. John McCain of Arizona, hinted that they might use military force against a nuclear-armed Iran.

Giuliani said that while such a strike would be “very dangerous,” nuclear arms “in the hands of an irrational person” such as Iran’s President Mahmoud Ahmadinejad would be even more so. McCain described such an attack as a last resort, but he said the option would be on the table in his Oval Office if Iran went nuclear and “our intelligence tells us that this is a real threat to the state of Israel, to other states in the region.”

If the country is looking for the next president to take a more gentle and diplomatic posture toward potential enemies around the world, it will likely find the Democratic options more appealing.

Only Sen. Hillary Rodham Clinton of New York instinctively called for military retaliation in answer to a question during her party’s first debate about responding to terrorist attacks on U.S. soil. The others instead talked first about managing the emergency response and pursuing international dialogue, only raising the prospect of military action later in the debate.

McCain won the tough-guy award of the GOP night in an exchange with former Gov. Mitt Romney of Massachusetts, who had been asked to explain his recent comment that it was “not worth moving heaven and earth spending billions of dollars just trying to catch” al Qaeda leader Osama bin Laden. At the debate, Romney obviously sensed a political need to amend that statement, saying that bin Laden “is going to pay, and he will die.”

That left an opening for McCain, who had termed Romney’s initial comment “naive.” Recalling that bin Laden was responsible for the deaths of thousands on Sept. 11, 2001, McCain said, “We will do whatever is necessary. We will track him down. We will capture him. We will bring him to justice, and I’ll follow him to the gates of hell.”

Some might find this tough talk a bit stale and hollow after so many years of George W. Bush sounding like a Wild West sheriff tracking down the bank robbers. But to many voters the terrorist threat remains quite real and worthy of tough talk that keeps military options wide open. It would take just one more attack on U.S. soil to bring many more voters in line with that thinking.

How best to keep America safe from terrorism still looms as the threshold question in the next presidential election. Only the candidates who make the electorate comfortable on this score are likely to be heard on other topics. And this first round of debates served as a test of wills for how the contenders would command the nation’s defense.

The trouble for Republicans in their debate was that, while trying to show strength on national security, they were forced to reckon with the inconvenient truth of how badly things are going for a president from their own party. It is tough for the GOP to maintain its image as the most competent and trustworthy on national defense now that most voters view Bush’s management of the war in Iraq as bordering on disaster.

Consequently, the GOP debaters had to balance what seems like a contradiction — supporting a mismanaged war. Unlike the Democrats, most Republican debaters would keep the current level of troops in Iraq, but even while voicing support for the Bush administration some went out of their way to simultaneously bash its war handling.

Former Gov. Mike Huckabee of Arkansas was the most colorful in backing the war while trashing its leadership. “Clearly, there was a real error in judgment,” he said, “and that primarily had to do with listening to a lot of folks who were civilians in suits and silk ties and not listening enough to the generals with mud and blood on their boots and medals on their chest.” McCain’s balancing act on this point focused on contrasting past errors against a current policy that he considers workable. “The war was terribly mismanaged,” he said. “But we have a new strategy and a new general.”

Watching the Republican candidates struggle with the uneasy facts on the ground in Iraq, it was easy to see how critical this war’s fate has become to their party’s chances for victory in 2008. No matter how tough they sound on questions of national security, their rhetoric might not be heard if this GOP-sponsored war looks as bad to voters 18 months from now as it does today.

Contributing Editor Craig Crawford is a news analyst for NBC, MSNBC and CNBC. He can be reached at ccrawford@cq.com.