The candidates planned to use their appearances before the Republican Jewish Coalition to boost their pro-Israel bona fides. But the mass shooting in San Bernardino, California -- the deadliest since the 2012 massacre in Newtown, Connecticut -- once again inserts the issues of violence, security and gun control into the 2016 race.
The day opened with a moment of silence for the victims, and the first speaker, Texas Sen. Ted Cruz, held another one at the opening of his speech.
He also said the murders show the nation is "at war" with terrorism.
"At this point the details of what happened in San Bernardino is still unclear," Cruz said. "All of us are deeply concerned that this is yet another manifestation of terrorism, radical Islamic terrorism here at home."
Sen. Marco Rubio was slightly more measured in his remarks, and only briefly touched on the shooting.
"We don't know all the facts yet, but we certainly have learned some facts that are concerning," Rubio said, saying his "prayers" were with the victims.
In contrast, South Carolina Sen. Lindsey Graham, who is languishing at the bottom of the polls, devoted most of the beginning of his speech to attacking Cruz for his hard-line positions, telling the audience he guarantees Republicans will lose the election with hard right immigration policies and opposing exceptions to abortion restrictions for cases of rape.
"Not the speech you thought you were going to hear, right?" Graham said. "Not the speech I thought I was going to give."
Still, the vast majority of the conference will serve as a forum for the candidates to make their foreign policy pitches before the RJC, a group of influential conservative Jews looking for a candidate strong on Israel and for an active U.S. role in the Middle East. With the Paris terrorist attacks and crisis in Syria putting national security in sharp focus in the race, candidates' performances may speak volumes about their viability with the Republican electorate.
Cruz and Graham both still dedicated a significant portion of their speeches to supporting Israel, opposing Iran and fighting terrorism.
Special attention Thursday was on GOP front-runner Trump and two senators rising in the polls: Rubio and Cruz. Trump led the new Quinnipiac University poll released Wednesday morning with 27%; Rubio and Cruz are at 17% and 16%, respectively, with Carson also at 16% as he continues to fall.
Trump announced Wednesday night a planned trip to Israel
, and spent most of his speech making jokes about his familiarity with the crowd.
"I know everybody in this audience," he joked at one point after recognizing an associate in the front row.
But he also conceded that the room was not his chosen crowd, and got boos from the audience when he refused to take a position on whether Jerusalem should be recognized as the capital of Israel.
"You're not going to support me even though I'm going to be the best thing that ever happened to Israel," Trump had said earlier. "And I know why you're not going to support me, it's because I don't want your money."
In contrast, the Florida and Texas senators are both comfortable speaking about foreign policy and have historically pro-Israel stances, with Cruz making targeting evangelical voters a priority, especially as Carson has struggled of late, including on foreign policy issues. Both were clear audience favorites for their speeches Thursday morning.
Kentucky Sen. Rand Paul was unable to make his speaking time at the forum due to votes in the Senate. All the other senators had morning speaking slots.
The senators are also vying for support of Sheldon Adelson, the casino magnate expected to spend millions of dollars backing a pro-Israel presidential candidate. Adelson's spokesman Andy Abboud said the billionaire will not be in attendance.
The audience is larger than just those in the room, however. Gallup polls show that 83% of Republicans side with Israel over Palestinians, up steadily from 53% in 2001, and evangelical voters in particular favor a pro-Israel foreign policy. Thus far in the race, those themes have mostly played out as GOP candidates have railed against President Barack Obama and also his nuclear weapons deal with Iran.
Each candidate gets 30 minutes, which includes opportunities for questions.
Tevi Troy, president of the American Health Policy Institute and a former George W. Bush administration official, said he expects Trump will have to show knowledge and mastery of foreign policy in order to impress the well-informed audience. Cruz and Rubio will have to live up to expectations. Carson had a chance rehabilitate himself on the foreign policy front. The rest of the candidates will be looking to have a breakout performance that could send them back into the top tier.
Jeb Bush, for instance, will come out strongly in support of Israel and highlight his long track record of supporting the Jewish state, said Former House Majority Leader Eric Cantor, a co-chairman of Bush's campaign. Carly Fiorina has often referred to Israeli Prime Minister Benjamin Netanyahu as her "friend" on the trail. And New Jersey Gov. Chris Christie will seek to avoid a repeat of his speech last year to the group, in which he ruffled feathers by referring to "occupied territories," as he continues to make the case that he is the most experienced candidate in the race on national security.
Carson, however, failed to impress the crowd, and delivered an uncharacteristic written address. Carson said he would be reading his remarks in order to make sure he made all the points he wanted to, but the wooden speech that was heavy on Israeli history and statistics failed to strike a chord with the audience.
He also several times throughout the speech failed to correctly pronounce Hamas, the Palestinian terror group that is one of Israel's biggest adversaries.
At one point, he described the Middle East as "really complicated."
"He missed a big opportunity," said former White House press secretary and RJC board member Ari Fleischer. "He read a good speech but the way he came across, it just doesn't work, you can't read a big lengthy policy wonky speech like that -- you have to make an emotional connection with the audience and he failed."
"He didn't advance his goal of showing any foreign policy," Fleischer added.
As for Trump, Fleischer said he entertained the crowd, but didn't impress.
"Trump's speech was wildly entertaining, it was enjoyable, but he comes across as if he lacks knowledge and lacks substance and doesn't know any of the nuance of the issues," Fleischer said. "For a group that wants to hear his position on an undivided Jerusalem and the '67 borders, he either didn't have a position because he doesn't know the issues or he made a mistake by not saying it."
The Paris attacks have put the spotlight again on ISIS and international terrorism, and that will be reflected at Thursday's event.
"There's no question" that the Paris attacks have made the RJC forum even more important, said Cantor, who was the highest ranking Republican Jew before losing a GOP primary in 2014. "We are in the process of nominating and electing a commander in chief. The gravity of the threat that continues to present itself as far as Israel is concerned reflects the gravity of the threat to the free world."
For her part, Fiorina focused on the Bernadino shooting, and used remarks lifted from her stump speech to pitch to the group.
"Hillary Clinton was tweeting about gun control while we learned that radicalized Islamic terrorists were building pipe bombs," the former Hewlett-Packard CEO said, one of the final 2016ers to speak, adding later. "The murder the mayhem that we see unfolding in Paris in Beiruit, San Bernardino are a direct consequence of this administration's polices. We cannot lead from behind."
Winning over the room will have more implications than amplifying a candidate's image: It will have an impact on the money, as well.
"The RJC is an excellent and skilled organization at bundling dollars in favor of preferred candidates," Troy said. "This is going to be a chance for candidates to talk candidly in real terms about foreign policy after Paris, in the context of Syria, and I think as a whole Republican candidates are going to be able to contrast their understanding of threats facing the country in contrast to the last seven years."