So far, foreign policy is driving the race for the 2016 Republican presidential nomination, with each potential contender vying to sound more hawkish than the next. Send U.S. ground troops to fight the Islamic State in Iraq and Syria? Bring it on.
"We didn't start this war, nor did we choose it. But we will have the will to finish it," former Texas Gov. Rick Perry said at the recent Conservative Political Action Conference. He said the self-styled caliphate, known as ISIS, "presents the biggest threat to national security since communism."
The possible GOP candidates also want a U.S. foreign policy that won't compromise with Iran on its nuclear ambitions, that will be even tougher with Vladimir Putin's Russia, and embrace Israel even more tightly.
"This president is the first president, I believe, in the World War II-post World War II era that does not believe American power is a force for good in the world," former Florida Gov. Jeb Bush said at an Iowa appearance last weekend.
All this talk represents a sharp departure from elections in 2008 and 2012, dominated by a slumping economy and lingering public weariness with the wars in Afghanistan and, especially, Iraq.
The candidates don't talk much about former President George W. Bush (including his brother Jeb) or mention the war Bush launched in Iraq, but the muscular rhetoric sounds similar to that heard during the administration of the last GOP president.
"Very few presidential elections are mainly about national security and foreign policy, but this next one could be," said Clifford D. May, president of the Foundation for Defense of Democracies, a conservative think tank.
"People at this moment are feeling very insecure about the international situation," May said. "Iran, for years considered by the U.S. government the chief state sponsor of terrorism, is seen as likely to get nuclear weapons. We have ISIS in Syria and Iraq, and the rise of Islamist terrorist groups in a dozen other countries. That worries people."
Many Republican voters who were wary of engagement after Iraq are willing to back intervention again, polls show, and approval of President Obama's handling of national security has dipped. And with the economy continuing to rebound, party strategists note, foreign policy may offer the GOP its best opportunity to draw a contrast with Democrats.
In 2009, about 53 percent of Republicans said the nation should "mind its own business" internationally and let other countries take care of themselves, according to a Pew Research Center survey.
But in a Pew poll last month, 67 percent of Republicans favored the use of ground troops to fight the Islamist extremists in Iraq and Syria, compared with 32 percent of Democrats.
Overall, the public is closely divided on whether to use ground forces, but the partisan differences on the question - and on the best way to fight terrorism in general - may help explain the hawkishness of the Republicans' recent foreign-policy messages.
In the latest Pew survey, 47 percent of the public said "overwhelming military force" was the best way to halt terrorism; 46 percent agreed more with the idea that an overreliance on force foments hatred that leads to more terrorism.
By contrast, 57 percent in a Pew poll last year agreed that too much force can be counterproductive.
The partisan divide is huge, Pew found.
These days, 74 percent of Republicans say "overwhelming force" is the way to go, up from 57 percent a year ago, compared with 30 percent of Democrats who agree (virtually unchanged from the 29 percent who agreed in the 2014 survey).
Recent polls have also given Republicans an edge over Democrats on foreign policy, a GOP strength for the last three decades that had all but evaporated in the wake of the Iraq war.
Gov. Christie in his appearances as a possible candidate often attacks Obama as a weak leader who has diminished the standing of the United States abroad.
In Concord, N.H., recently, he said Obama was "like a man wandering around in a dark room feeling along the wall for the light switch of leadership."
The debate intensified last week as 47 GOP senators wrote an open letter to Iranian leaders alleging that Obama was circumventing Congress in negotiating an agreement to curtail Tehran's nuclear ambitions, and warning any deal could be overturned in a future administration.
The party hawkishness poses a challenge to the presidential ambitions of Sen. Rand Paul of Kentucky, who has advocated a more restrained approach to U.S. involvement abroad.
"It could become a problem if he is perceived as a true isolationist, but he's already making moves to suggest he's got a more nuanced view than that," said GOP strategist Charlie Gerow, of Harrisburg, who has worked on presidential campaigns.
Indeed, Paul signed the letter to Iran and, while he has been skeptical of using U.S. ground forces against ISIS, he has also advocated a separate country for the ethnic Kurds and directly arming them in their ongoing fight against the extremist group. He has also said he would maintain a robust military to project strength abroad.
For now, foreign policy continues to rank high on voters' list of concerns in the early-voting states.
In New Hampshire's Granite State Poll last month, 20 percent of likely Republican primary voters chose national security as the issue that would decide their vote - ahead of immigration, health care, the budget and federal debt, and taxes. Still, 29 percent mentioned jobs and the economy.
"We're calling it a foreign-policy election, but I'm not convinced yet," said Andrew Smith, pollster and political scientist at the University of New Hampshire who conducted the survey. Right now, he said, events in the news cycle demand attention on the issue, but "most voters won't focus for another year, and I'm not sure where they'll be."
Percentage of Republicans who favor using ground troops to fight Islamic militants.
Percentage of Democrats who do.
Percentage of Republicans who say "overwhelming military force" is the best way to defeat terrorism.
Percentage of Democrats who do.
Percentage of likely Republican voters who say national security is their primary concern.
SOURCES: Pew Research Center, Granite State Poll