Here are highlights from CNN's Republican presidential debate on Dec. 15 in less than two minutes. (Sarah Parnass/The Washington Post)

There were calls to “carpet-bomb” gathering places of Islamic State fighters and kill family members of suspected terrorists. There were proposals to arm Kurdish forces, shoot down a Russian jet if it entered a no-fly zone and shut down the Internet in war-torn areas. And there were suggestions of banning Muslims from entering the United States and monitoring activity inside mosques.

The presidential debate here this week crystallized the Republican Party’s growing consensus on national security and its strikingly hawkish response to threats at home and abroad, with the candidates vividly channeling the alarm and fear coursing through the GOP base.

“America is at war,” Sen. Ted Cruz of Texas declared in his opening statement. “Our enemy is not violent extremism. It is not some unnamed malevolent force. It is radical Islamic terrorists. . . . If I am elected president, we will hunt down and kill the terrorists. We will utterly destroy ISIS.”

Using bellicose language at a moment of pitched voter anxiety, many of the candidates committed themselves to a confrontational set of policies that, while energizing conservative activists, could prove difficult to carry out internationally and pose the risk of a backlash from war-weary swing voters next fall.

Thomas H. Kean, a former New Jersey governor who co-chaired the 9/11 Commission, said the GOP candidates were probably reacting to the suddenly hawkish mood of the electorate that is showing up in polls.

How GOP candidates traded jabs in the security-focused CNN debate, in 5 charts

But Kean warned, “You can get locked into some of these positions if you get elected. It all sounds fine now in a primary, but Republicans might be sorry at the end of the year if they’re in the White House and the new president has to adjust to changing circumstances.”

Pollster Geoff Garin, who advises a super PAC backing Democratic front-runner Hillary Clinton, said the GOP debate opens the door for Clinton to be “the strong and steady grown-up in the room.”

“What [voters] appreciate in a presidential leader is quiet strength, and what they heard last night was a ton of dangerous bluster,” Garin said Wednesday. “Being the party of military adventurism may be passable politics for their nominating process, but it is very likely to cause lots of doubts and concerns in a general election.”

In a Tuesday speech before the GOP debate, Clinton said that “shallow slogans don’t add up to a strategy. Promising to carpet-bomb until the desert glows doesn’t make you sound strong — it makes you sound like you’re in over your head. Bluster and bigotry are not credentials for becoming commander in chief.”

The GOP hopefuls on the debate stage painted a dark and frightening portrait of the homeland’s security, warning that the military is not equipped to wage war against terrorists and that no community is safe after recent attacks in Paris and San Bernardino, Calif.

Most of the candidates portrayed President Obama as incapable and unknowing and posited that the Islamic State, also known as ISIS and ISIL, could be extinguished only if America’s president were more decisive and used massive force.

CNN's Republican presidential debate in Las Vegas was only the penultimate lap for the GOP candidates, not the finish. The Washington Post’s Robert Costa talks about about which candidates were the strongest and which still have a long road ahead. (Alice Li/The Washington Post)

“Look, we need toughness. We need strength,” said Donald Trump, the billionaire mogul and national GOP front-runner. “We’re not respected, you know, as a nation anymore. We don’t have that level of respect that we need. And if we don’t get it back fast, we’re just going to go weaker, weaker, and just disintegrate.”

The problems the United States faces around the world are far more complicated than what was suggested on the debate stage, with global consequences that would ripple from each proposed action. For example, arming the Kurds, which many candidates supported, could alienate Turkey, which is a key U.S. ally in the Syrian conflict and fears the creation of a de facto Kurdish state.

New Jersey Gov. Chris Christie, who warned that every community is in danger after the carnage in San Bernardino, showed a willingness to engage in military confrontation with Russia.

Asked whether he would shoot down a Russian aircraft if it encroached on a U.S.-imposed no-fly zone over Syria, Christie said: “Not only would I be prepared to do it, I would do it. . . . Yes, we would shoot down the planes of Russian pilots if in fact they were stupid enough to think that this president was the same feckless weakling.”

But the CNN debate also exposed fault lines among the candidates — especially over the breadth of federal surveillance and counterterrorism programs — and showed how much the legacy of President George W. Bush’s Iraq War still hovers over the party.

One of the most meaningful divisions surfaced on the subject of military interventions in the Middle East since the Sept. 11, 2001, terrorist attacks. Some candidates, including Sen. Marco Rubio of Florida and former Florida governor Jeb Bush, said the United States has a moral and pragmatic obligation to maintain a forceful presence abroad.

But other candidates, including Trump and Sen. Rand Paul of Kentucky, condemned past interventions in the Middle East — and made little distinction between those led by George W. Bush and those led by Obama. “The policies that we’ve suffered under other presidents have been a disaster for our country,” Trump said, noting his long-stated opposition to the Iraq War.

Paul explicitly blasted fellow Republicans for having supported past regime changes. “They want it in Syria. They wanted it in Iraq. They want it in Libya,” he said. “It has not worked. Out of regime change you get chaos. From the chaos you have seen repeatedly the rise of radical Islam.”

Despite such differences, the overall tone of the nine debaters on the main stage Tuesday night was uniformly aggressive.

Paul, who stands out for his resistance to foreign engagement, used muscular language throughout. Even Ben Carson, the soft-spoken doctor who has been criticized for his relative lack of foreign policy knowledge, spoke in harsh, sometimes apocalyptic terms to describe his worldview.

Carson said surveillance of suspected terrorists should extend to “a mosque, a school, a supermarket, a theater — you know, it doesn’t matter. If there are a lot of people getting there and engaging in radicalizing activities, then we need to be suspicious of it. We have to get rid of all this PC stuff. And people are worried about if somebody’s going to say that I’m Islamophobic or what have you — this is craziness, because we are at war.”

Trump offered some of the most hard-line positions of the night. He defended his controversial proposal to ban most Muslims from entering the country and called for enlisting Silicon Valley engineers to help cut off Internet access in global conflict zones and for suspected jihadists. He also reiterated his vow to kill family members of suspected terrorists.

“I would be very, very firm with families,” Trump said. “Frankly, that will make people think — because they may not care much about their lives, but they do care, believe it or not, about their families’ lives.”

When criticized about this idea — Bush said it represented “a lack of seriousness,” while Paul argued that it would violate the Geneva Conventions — Trump replied, “So, they can kill us but we can’t kill them?”

On the campaign trail, Cruz has used tough and withering rhetoric on terrorism. He said recently in Iowa that he would “carpet-bomb” the Islamic State “into oblivion” and wanted to “see if sand can glow in the dark.”

Asked in the debate about his carpet-bombing plan, Cruz said he would target places where Islamic State fighters convene, although such an air assault undoubtedly could result in a large civilian death toll.

Under a Cruz presidency, he argued, “militants across the globe see that when you join ISIS that you are giving up your life, you are signing your death warrant.”

DelReal reported from Washington. Rosalind S. Helderman in Washington contributed to this report.

Correction: An earlier version of this article referred to Rand Paul by his father’s name, Ron.