In the weeks since the Paris attacks, Republicans have been outspoken about the potential security risk posed by refugees from countries where ISIS has established strongholds from coming into the United States.
But when pressed on Donald Trump's call for "a total and complete shutdown of Muslims entering the United States," many of this cycle's most vulnerable senators were slow to respond.
It's rare for down-ballot candidates to criticize the party's front-runner before any votes are cast. But this isn't an ordinary election, with Trump repeatedly making over-the-top statements that have only bolstered his standing.
His latest remarks aren't likely to damage the GOP frontrunner in the short run, Republican consultant Brian Walsh said Tuesday. "The people who are supporting Trump generally agree with those outrageous statements and he channels their anger."
That puts Republican Senate candidates in a precarious position as they try to hold Trump's base without losing general election voters.
"On the one hand, you don’t want to alienate his supporters," Walsh said. "On the other hand, standing with him on something like this could alienate middle of the road voters as well."
Florida Rep. David Jolly, who's vying for the the GOP nomination in Florida's crowded Senate primary, pulled no punches when he called for Trump to drop out of the presidential race shortly after his remarks on Monday.
None of the senators facing re-election next year went that far.
Tuesday morning, Pennsylvania Sen. Patrick J. Toomey joined Republican presidential candidates in denouncing Trump on Twitter. "Trump is wrong," he tweeted. "We should have a security test, and it should be bullet proof," Toomey said.
When asked for statements Tuesday, other vulnerable Republicans who have called for a halt to accepting Syrian refugees reiterated that a strong test is needed to determine who can and cannot enter the country, but clarified that it should not be based on race or religion.
Illinois Sen. Mark S. Kirk, the most vulnerable Senate Republican , who has already made Syrian refugees a campaign issue in a recent TV ad , offered a strong rebuke to Trump's proposals, calling it "anathema to American values," but not before blaming President Barack Obama's administration for a climate of uncertainty.
"The failure of this Administration to reassure Americans of our strategy and security has created an environment of fear," he said in a statement Tuesday afternoon.
Responding to Trump's comments without mentioning him, Ohio Sen. Rob Portman said that such a test "is counter to constitutional principles of religious liberty."
"Of course we should vet everyone who wants to come to our country to ensure they don't pose a security risk, but it should be done based on factors that relate to security,” he added.
Talking to reporters Tuesday , New Hampshire Sen. Kelly Ayotte hesitated to zero in on Trump. “You’ve got a lot of presidential candidates in this race, so I’m not going to spend my time with what they’re doing. I’m going to spend time on what I’m doing.”
In a statement her office released later that day, Ayotte said a religion-based test "would be inconsistent with the First Amendment to the Constitution," before calling for "fact-based risk assessments" and touting her co-sponsorship of legislation to strengthen the Visa Waiver Program.
This cycle's second most vulnerable Republican , Wisconsin's Ron Johnson, sponsored the Senate bill that would add additional layers of security checks to Syrian and Iraqi refugees. But his campaign did not immediately issue a statement when asked for comment Tuesday. Spokesman Brian Reisinger followed up to say, "This is not a serious or well-thought-out policy proposal."
"We’ve always been a country with a big heart, and we don't need a religious test to fix our immigration problems," Johnson said through Reisinger.
Ron Bonjean, a GOP consultant and partner of Walsh's at the Washington, D.C., based Rokk Solutions, said Senate candidates should be proactive in their responses to Trump before waiting for the inevitable questions on the campaign trail.
“The better thing to do is to get in front of it and disavow those comments,” Bonjean said. “The Republican candidates that really matter are in swing states or they’re vulnerable. They should do all they can to separate themselves from Donald Trump or else they’re going to have a tougher time in the general election. And it’s not hard to do, the presidential candidates are doing it.”
Long before Trump’s most recent remarks, in a seven-page private National Republican Senatorial Committee memo from September, executive director Ward Baker told Senate candidates to adopt Trump’s style if not his political brand, urging candidates to leave plenty of room between them and the front-runner’s controversial remarks.
According to The Washington Post, which obtained the document last week, the memo implied “the national party would back Trump if he secured the nomination — managing his candidacy rather than disowning him as the standard-bearer.”
But some of the party’s standard-bearers, including Speaker Paul D. Ryan, went out of their way to distance the party from Trump’s comments Tuesday.
Republican National Committee Chairman Reince Priebus would only say that he doesn’t agree with Trump’s comments, according to the Washington Examiner .
Strategists say candidates have to balance their commitment to protecting national security, being mindful that Trump's comments reflect a deeper sentiment among a certain element of the GOP, and making it clear that Trump went too far.
"Trump has said a lot of outrageous things, but this takes things to a new level," Walsh added.