Republican lawmakers on Capitol Hill are standing apart from their presumptive presidential nominee yet again — but this time in the aftermath of a major terror attack on the American homeland, an event that historically has brought parties together, not driven them apart.

Donald Trump, the presumptive nominee, responded Monday to the Orlando terror attack that left 49 clubgoers and the shooter dead by reiterating his support for a temporary ban on the immigration of Muslims and calling for an expansion of it to encompass “areas of the world where there’s a proven history of terrorism against the United States, Europe or our allies.”

That drew fresh condemnations from House Speaker Paul D. Ryan (R-Wis.), who called Tuesday for “a security test, not a religious test” for immigrants.

“I do not think a Muslim ban is in our country’s interest,” he told reporters. “I do not think it is reflective of our principles, not just as a party but as a country.”

There is already a rift between Trump and some of his fellow Republicans on Capitol Hill, many of whom have openly counseled him to moderate his tone and assume a more presidential mien.

But Trump’s reaction to the Orlando attacks — perpetrated by the U.S.-born son of Afghan immigrants — has illustrated just how sharply he has broken with GOP orthodoxy on national security, terrorism and Islamic relations since the 9/11 attacks.

“Traditionally, it is a time when people rally around our country, and it’s obviously not what’s occurred, and it’s very disappointing,” said Sen. Bob Corker (R-Tenn.), the Foreign Relations Committee chairman who has praised Trump at times for his willingness to shake up politics.

Asked Tuesday about Trump’s reaction to the Orlando attack, Corker declined to praise him: “I have offered words of encouragement at important times but have been discouraged by the results.”

While Trump’s proposed Muslim immigration ban has largely gotten a chilly reception from Capitol Hill leaders, it is extremely popular among GOP voters. A Washington Post-ABC News poll conducted in December after the terror-linked attack in San Bernardino, Calif, found that 59 percent of Republicans supported the ban versus 38 percent who opposed it.

But only 36 percent of the population at large — and 38 percent of political independents — said they supported the proposed ban, the survey found, underscoring the fact that the rhetoric that propelled Trump to the top of the Republican field might alienate voters in a general election.

The differences between Trump and GOP leaders, meanwhile, go deeper than immigration policy.

Trump suggested Monday that American Muslims were not cooperating with law enforcement to combat radicalism: “They have to work with us. They know what’s going on. They know that he was bad. They knew the people in San Bernardino were bad. But you know what? They didn’t turn them in. And you know what? We had death and destruction.”

“If we don’t get tough, and if we don’t get smart, and fast, we’re not going to have our country anymore,” Trump said. “There will be nothing, absolutely nothing, left.”

Ryan, in contrast, drew a sharp distinction between terrorist radicals and Muslims at-large.

“This is a war with radical Islam; it’s not a war with Islam,” he said. “The vast, vast majority of Muslims in this country and around the world are moderates. They’re peaceful. They’re tolerant. They’re among our best allies, among our best resources in this fight against radical Islamic terrorism.”

In December, when Trump first proposed a Muslim immigration ban in the wake of a similar attack in San Bernardino, Calif., Ryan quickly denounced the proposal as “not conservatism” and “not what this party stands for.”

“Freedom of religion is a fundamental constitutional principle,” he said at the time. “It’s a founding principle of this country.”

Ryan endorsed Trump earlier this month, arguing that a Trump presidency would allow more conservative legislation to be passed than under a Democratic presidency. But Trump quickly tested Ryan by attacking a federal judge handling a civil case Trump is involved in, citing the judge’s Mexican heritage. Ryan denounced that as “the textbook definition of a racist comment.”

Now, the double-down on the Muslim ban has again put Ryan at odds with Trump on a matter on basic principle. As he left the podium Tuesday, Ryan was asked whether he stood by Trump; he did not respond.

Ryan last week oversaw the release of a national security policy agenda that touches on many of the themes Trump has seized on during his insurgent campaign but does not not go nearly as far as Trump has in several respects.

The agenda mentions improvements to the immigration system, for instance, tightening visa controls and stiffening application and screening procedures for refugees. But nowhere does it mention a geographic or religious test for entering the country.

“We are at war with Islamist terrorists,” the report says, and “we must act like we are fighting a war.” But that war “will not be won with bullets and bombs alone,” it continues. “It will be won by the force of our ideas.”

Top Republicans who have advocated for a more robust response to the Islamic State and other radical groups, as well as more precautions to protect the American homeland — such as Foreign Affairs Committee Chairman Ed Royce (R-Calif.) — have found themselves forced to thread a position between Trump’s Muslim-ban proposal and the existing policies of the Obama administration.

“I disagree with that, but I think those coming into the country should be vetted,” Royce said Tuesday.

A leading House GOP voice on national security issues, Rep. Adam Kinzinger (R-Ill.), an Air Force major, also broke sharply with Trump.

“I guess I appreciate Mr. Trump’s fieriness in talking about it, but you don’t do it by alienating the very people that we need, and those are moderate Muslims,” he said Tuesday. “We have to use the folks that frankly are not radicalized, which is the vast majority of Muslims, to win this war.”

“You can’t on one hand say we need other people to take care of their own business, and on the other hand alienate the very people we’re going to rely on to liberate the [Middle East] of Islamic jihadism,” Kinzinger added.

Kinzinger, who has withheld support for Trump, said it was “never too late” for Trump to change his ways.

“The purpose of not supporting him right now is to hope that he actually kind of wakes up from some of the comments he’s made,” he said. “Look, have fire, have passion. We’re not asking him to change who he is, but sound presidential and begin to morph into the role of leader, and I haven’t seen it.”