At a recent town hall back home in Omaha, Republican Rep. Don Bacon was confronted by one of his constituents who, like a growing number of conservatives, was displeased with the vast sums of U.S. weaponry and money being given to Ukraine. Why, this man wanted to know, does the congressman believe that after 18 months it remains in America’s best interest to continue bankrolling the war?

Bacon, a retired Air Force general, was ready. Russia, he explained, launched its invasion because Ukraine was growing closer to the United States, becoming more democratic, and posing an existential threat to the authoritarian rule of President Vladimir Putin and his desire to reclaim the Kremlin’s lost empire.

“I told the town hall: ‘When I was a kid, if you had a bully on the playground - that bully never stops unless he gets punched in the nose,” Bacon said later in an interview. “ ‘And so we’ve got to stand up to Putin here.’ “ But he said he included a caveat in that response too: “We shouldn’t give just a blank check to Biden. He’s got to justify why he needs this.”

The exchange in Nebraska is emblematic of a growing tension throughout the Republican Party, and among a small number of Democrats, as Congress begins anew the contentious process of considering just how big of a check President Biden can have to sustain the flow of U.S. assistance - and for how long lawmakers will keep the spigot open. American attitudes toward Ukraine are shifting, Capitol Hill is feeling the pressure as the country heads into an election year, and Ukraine’s highly anticipated summer offensive has made only minor territorial gains thus far. So, with each subsequent ask for funding, securing congressional approval is likely to grow more challenging, lawmakers and analysts say.

The White House in August sent lawmakers a supplemental budget request seeking $40 billion, more than half of which would go toward aiding Ukraine and related efforts intended to shore up NATO allies’ defenses and provide a cushion for other vulnerable countries impacted by the war. The funding, if approved, would bring total U.S. investment to $135 billion, according to an analysis by Mark F. Cancian at the Center for Strategic and International Studies.

As the war struggles onward, though, questions like the one aired in Omaha reflect a larger dispute that’s tearing at the GOP, whose raucous right flank is waging an aggressive campaign to rally public support for slashing Ukraine aid. If some Republicans had their way, the price tag on future assistance would be zero.

Republican leaders, Democrats and the White House insist that a majority of Congress continues to support helping Ukraine. Following a Thursday meeting with Senate leadership on the issue, Biden’s national security adviser, Jake Sullivan, acknowledged that lawmakers have “a lot of specific questions” about the administration’s policy and “constructive suggestions” for what ought to change. But he told reporters there remains a strong bipartisan will to uphold “America’s commitment.”

Nonetheless, the America-first agenda is posing seismic challenges for moderate Republicans as they work to convince the party’s increasingly wary base that standing with Ukraine, and alongside like-minded Democrats, is consistent with conservative fiscal values, essential for U.S. national security, and won’t amount to another “forever war” like Afghanistan - an argument pushed by the hard-right.

For Republicans, historically hawkish and supportive of American interventionism, the internal battle over Ukraine aid underscores what analysts say is the party’s broader struggle to define what it represents - a long-smoldering question that is expected to grow more torrid as the next election cycle heats up.

“I’m old enough to remember Ronald Reagan,” said Bradley Bowman of the Foundation for Defense of Democracies, a conservative Washington think tank, lamenting what he called the GOP’s “fight for its soul.”

“I just can’t imagine a Republican Party that is soft on the Kremlin,” he said, “that doesn’t understand the importance of security in Europe.”

The ‘blank check’ debate

Many of Kyiv’s most influential backers in the GOP believe that Biden hasn’t been supportive enough, and they are unabashed in their criticism of his management of the crisis. They have warned that uninterrupted aid is vital to Ukraine’s survival and further weakening Russia’s capacity to threaten the West. In the Senate on Wednesday, Minority Leader Mitch McConnell (R-Ky.), while jabbing the president, admonished detractors not to “compound his administration’s failures with failures of our own.”

“It is not the time to ease up. . . . It’s not the time for America to step back,” he said of U.S. support in Ukraine.

Though not explicitly aimed at the Republican-led House, McConnell’s remarks were an indication of the volatility there. Earlier this summer, as the chamber worked to advance its version of the annual defense policy bill, a bloc of 70 GOP lawmakers banded together in what was ultimately a failed bid to force a cutback on Ukraine assistance.

Rep. Brian Mast (R-Fla.), who says he will not vote for additional aid to Ukraine, criticized the administration for having offered Congress no coherent strategy, objective or timeline for the war, adding that he needs to see one he can back funding it. “I can support something, but I can’t support nothing. That’s how you get what happened in Afghanistan,” said Mast, an Army veteran who lost both of his legs in an explosion there.

For now, it is unclear when or even if Speaker Kevin McCarthy (R-Calif.), who has given mixed signals on Ukraine, will ask the House to vote on a supplemental budget request. (It was McCarthy who, last fall, said he did not back giving Kyiv a “blank check” only to say this past spring that he does support U.S. aid for Ukraine.) A spokesman said Friday that considering Biden’s latest funding request is not a priority.

“There has been a shift,” Bacon said of his party and the country. Seventy members is a minority, but it’s one-third of the Republican caucus, he noted.

“A lot of people responded to the politics and, you know, the polling,” he said, referencing recent data that suggests Americans’ good will is waning. “You see a lot of this B.S. propaganda out there,” he added, faulting the spread of misinformation and what he called “a lot of echo chamber and a lot of groupthink” within segments of his party. “I’ve seen a lot of stuff like: ‘A lot of these weapons ended up in terrorists’ hands, or being sold on the black market.’ That’s absolutely not true. We are tracking these weapons.”

The Republican presidential primary race also is playing a role in the intraparty clash over Ukraine. Former president Donald Trump, who holds a strong lead, has repeatedly scorned the security assistance program, telling interviewers that he would end the war “in a day” by forcing Ukrainian President Volodymyr Zelensky to make a deal with Putin - a suggestion Trump’s critics have read as capitulating to Russia.

At last month’s GOP primary debate in Milwaukee, businessman Vivek Ramaswamy’s hand shot up when moderators asked if any of the candidates would halt funding to Ukraine should they become president.

Ramaswamy, who cast America’s involvement in the war as “protecting against an invasion across somebody else’s border” when those resources could be better used to staunch illegal immigration to the United States, drew sharp rebukes from Trump’s former vice president Mike Pence and some of the other candidates.

Pence, who is polling in the single digits among voters, gave a fiery address this month further distancing himself from the brand of populism espoused by Trump and his “imitators” - declaring himself a “traditional conservative” and arguing for the continuation of robust support to Ukraine.

Rep. Joe Wilson (R-S.C.), who served in the Reagan administration, and currently chairs the Commission on Security and Cooperation in Europe, said he also has been disturbed by the shift. “The traditions of - in my view - of the Republican Party are for peace through strength, and supporting liberation and democracy around the world,” he said in an interview. “And so it’s somewhat startling to see that we now have a level of isolationism in the party.”

Both Republicans and Democrats say constituents’ questions about Ukraine have grown fewer and farther between since the initial rush of interest following Russia’s invasion last year.

Sen. Roger Wicker (R), who wears to work a lapel pin bearing the U.S. and Ukrainian flags, said that he received “hardly any pushback” about his support for Ukraine funding when, during last month’s congressional recess, he spent time back home in Mississippi. But he has also tired of those who do.

“I lose patience with people saying ‘We need to quit writing a blank check’ [because] we’re not writing a blank check.” To the skeptics, he said, “I think we have to ask the question of what the alternatives are? What does the world look like, and what does American foreign policy look like, when we cease supporting Ukraine and leave them at the mercy of a Czarist like Vladimir Putin? It would be an earth-shattering geopolitical change that would harm the United States for generations.”

Americans’ attitudes are shifting

A recent Fox News poll found that while most Americans still believe the United States should be supporting Ukraine, a growing minority - 36 percent, up from 26 percent in December - said the help should be less. Within the Republican Party specifically, though, Fox found that a 56 percent majority now say U.S. aid should be rolled back. Less than 40 percent of respondents felt that way in late 2022.

A separate poll released last month by CNN found that 55 percent of respondents don’t want Congress to authorize any additional Ukraine funding.

On the far-left, some Democrats also have voiced concerns about the amount of aid being given to Ukraine, calling instead for greater spending on domestic programs. A handful of progressive Democrats have previously voted against funding for Ukraine, and some last year appealed for a negotiated solution to the war, later rescinding that request.

White House officials say they remain optimistic that the additional funding for Ukraine will pass. But members of both parties have quietly complained that the administration has failed to help them sell the idea to constituents by making a more convincing argument.

Matt Dimmick, who served as director for Russia and Eastern Europe on Trump’s National Security Council, credited the Biden administration for “doing all the right things, for the most part, except for on a slower scale.” But, said Dimmick, now with Spirit of America, an organization providing nonlethal assistance to Ukraine, “nobody in the administration that I’ve heard has come out and said: ‘Here’s why.’ It’s always been sort of mealy-mouthed.”

Sullivan said in recent days that “the president has made clear, repeatedly, since this conflict began what the stakes are for the American people: that letting Russia run roughshod over Ukraine would put Europe at risk. And we know what happens when a marauding, aggressive, hostile power places the continent of Europe in military risk. It comes at a much greater cost, not just in American treasure, but in American lives later.”

There are many Republicans who agree. But Rep. Jim Baird (R-Ind.) said that voters in his largely rural manufacturing district west of Indianapolis, are “concerned about the country, our country, America. And so that’s going to take a precedence over anyone else.”

In the past few years, the cost of filling up the gas tank on his pickup truck has risen from $50 to $100, Baird said - a fact, he said, that should underscore why his constituents could soon lose their tolerance for funding a war that seems foreign and far away.

“We’re going to have to be smart about the kind of help we can give them,” he said. “. . . You know, none of us want another 20 year war.”

Bacon also said he worries about the American public’s patience waning. “At some point, maybe this opportunity closes to help them out,” Bacon said. “And I don’t want that to happen, but I think we should be going in pretty hard right now and trying to get the job done.”

Matt Viser and John Hudson contributed to this report.