Tuesday morning’s vote on the Senate floor, which saw more than half of Senate Republicans vote against aid to Israel, Ukraine and Taiwan, crystallized the emerging isolationist instinct in Republican politics, which is now drawing in even some of the party’s most committed foreign policy hawks.

It’s a trend that seems primarily driven by former President Donald Trump’s America First ideology, which has been embraced by much of the Republican grassroots base. Trump has long been dismissive of the U.S.’ NATO commitments — and is now urging lawmakers to restructure military funding to U.S. allies in the form of a loan. 

The stunning opposition of hawkish Sen. Lindsey Graham (R-SC) — a close ally of Trump — to aid to Ukraine and Israel captured headlines in Washington on Monday, but other once-stalwart pro-Israel, pro-Ukraine Republican senators are following a similar path and voted against the security aid package.

Sen. Tom Cotton (R-AR) accused Democrats of failing to seriously pursue border policy, forcing Republicans’ hands against the bill, and lambasted the relatively small proportion of non-military spending included in the bill as handouts to Hamas terrorists and left-wing environmental and social causes. While voting against the bill, he blamed “Joe Biden’s failures and his weakness” for crises around the globe.

“After four months we saw that the Democrats are more ideologically invested in open borders than they are a secure border or for that matter, aiding our friends around the world,” Cotton said on the Senate floor. “If this bill doesn’t pass into law, it should be a template for the future and hopefully legislation that might come back to us from the House. However, the bill still includes $19 billion in nondefense spending.”

Sen. Marco Rubio (R-FL), in a lengthy floor speech, said that defending Ukraine is a key national security interest that could define the future of the global order. But he also dismissed the notions that Russia could fully conquer Ukraine, or Ukraine could fully defeat Russia, arguing that the conflict must come to a negotiated resolution.

Rubio suggested that voters don’t understand why supporting Ukraine should be a priority and believe that lawmakers should be giving more attention to border security.

Democratic and Republican lawmakers spent months negotiating a bipartisan border deal, which Republicans quickly rejected under pressure from Trump and House Republicans.

“The overwhelming majority of people would say, ‘I don’t have anything against Ukraine. I hope Ukraine wins. I don’t like Putin. I get everything you said about our national interest,’” Rubio said. “But how can we focus on that and not at least also focus on what’s happening to us in our country, at our southern border? It makes no sense to people.”

“When was the last time you saw Congress working on something that matters directly — a priority of the American people?” he continued. “It doesn’t happen.”

Graham, likewise, indicated his new posture is an acknowledgement of shifting pressures from his base.

“I want to help Ukraine,” Graham said in a major foreign policy address on Sunday. “But having said all of that, for me to be able to convince people in South Carolina to continue to support conflicts overseas, I have to prove to them I get it when they tell me what about their own country. So I’m not going to Munich, I’m going to the southern border.” 

Graham, long a fixture of overseas foreign-policy confabs, announced that he would skip the annual Munich Security Conference for a trip to the U.S. border with Mexico.

“To my House colleagues, I am voting no, against aid that I believe is very much needed, and I’ve been an advocate for, to let you know I’m listening to you,” Graham added. 

Graham sought to distinguish his approach — along with Trump’s “America First” policy — from the hardline isolationism of some of his colleagues, insisting that “if ‘America First’ is isolationism, count me out — I don’t believe it is.” But there’s ample evidence of Trump’s isolationist instincts from his time in office and his remarks in just the past few days.

Even as they spoke against the Senate aid package, many Republican critics focused their attacks on the Ukraine portion of the legislation. They insist that they still support Israel aid and would have voted for it as a stand-alone bill, which failed the House last week. Many described Ukraine, by contrast, as essentially a lost cause.

The GOP’s foreign policy shift has been pushed along by major influencers and thought leaders on the right wing, such as the Heritage Foundation, which has been advocating against further aid to Ukraine, and Tucker Carlson, the ousted Fox News host who this week suggested that he’s not in favor of the U.S.’ continued support for Israel’s war against Hamas.

Robert Greenway, director of the Allison Center for National Security at the Heritage Foundation, told Jewish Insider that there are fundamentally different considerations at play in supporting aid to Israel versus Ukraine. Israel relies on Washington more than Ukraine does, he argued. 

“When it comes to military and financial support for Israel, the U.S. is it. We’re it. There is nobody else,” said Greenway. “Even though it’s the subject of much debate, for Ukraine that’s clearly not the case. There is a broader constellation of European partners and allies that are and will continue and should continue to provide more support to Ukraine. That’s not the case for Israel.”

But the House’s insistence late last year on offsetting Israel aid with cuts from elsewhere in the government, and the emerging push from Trump to restructure foreign aid as a loan, could foreshadow a more skeptical approach from Republicans going forward. A handful of conservative Republicans — who wield outsized power in the House, as currently constituted — voted last week against Israel aid without offsets.

Nachama Soloveichik, the communications director for Nikki Haley’s presidential campaign, warned on Tuesday, “Just watch… This new Republican Party will soon throw Israel under the bus.”

Trump’s Israel policy in a potential second term could be shaped in part by staffing changes — his son-in-law Jared Kushner, who helped broker the Abraham Accords, said this week he would not rejoin a Trump White House.

The Republican Jewish Coalition urged members of Congress to support the supplemental funding bill. The organization thinks the U.S. should take a strong approach to global aid, and not  limit it to Israel. 

“This is about American values. This is about democracy. This is about protecting the innocent against terrorism,” said the RJC’s national political director, Sam Markstein. “Whether it’s the terror caused by Hamas on October 7, or the terror caused by Putin invading Ukraine, or the potential terror of a Chinese invasion of Taiwan, they’re all connected. And so it’s in our national security interests, and in all these countries’ national security interests, to be supported by the Republican Party.” 

Tuesday’s vote highlighted the growing gulf between the GOP’s elder statesmen and its younger members on foreign policy: Most senior Republicans voted in favor of the aid package, while many more junior lawmakers elected in the post-Trump era opposed it.

As has been the case for years, even Republicans with more traditional foreign policy views seem loath to acknowledge Trump’s isolationist tendencies. Sen. Thom Tillis (R-NC), one of the most vocal proponents of the aid package, blamed Trump’s NATO comments on his “briefers,” while Sen. John Cornyn (R-TX) said Trump’s comments shouldn’t be taken “literally.”’

Trump said that the U.S. should not defend NATO members that do not meet defense spending targets, and that he’d encourage Russia to “do whatever the hell they want” to such countries.

The GOP’s isolationist shift may only accelerate in the coming years, as some of its more mainstream members jump ship from the dysfunctional House of Representatives. For instance, Rep. Mike Gallagher (R-WI) — a hawkish, pro-Ukraine lawmaker who chairs the House’s bipartisan committee on China and was seen as a rising star — announced last week that he is retiring at the end of this year.