(The Hill) — President Joe Biden’s reelection bid on Tuesday set in motion an incoming clash with leading Republican candidates in the 2024 White House race over the war in Ukraine, with the outcome potentially proving decisive for Kyiv.

Biden’s vow to stick with Ukraine until the war is won stands in stark contrast to former President Donald Trump’s promise to negotiate peace as soon as he reenters America’s highest office.

Other GOP candidates and potential candidates like Florida Gov. Ron DeSantis are offering mixed views on the war, setting it up to be a central foreign policy issue in the months ahead.

Andrew Albertson, executive director of Foreign Policy for America, said the 2024 election is evolving into a “leadership test” when it comes to foreign policy and the Ukraine war.

“On the one hand, you’ve got the normal traditional role that the U.S. has played as a principled leader in the world, in this case, rallying our allies to support Ukrainians to defend themselves against Russia’s horrific assault,” he said. 

“And then you have agents of chaos on the other side, who seem intent on throwing away that leadership position,” he added, referring to far-right House lawmakers.

Ryan Walker, vice president of government relations at conservative-leaning Heritage Action, said the Biden administration lacked a long-term vision for the war, or a cohesive strategy for the billions in aid Washington is sending to Kyiv. 

“Beyond questions of public accountability … and long-term strategic plans from the administration or any candidate running for office, there also needs to be a discussion of the impact of drawdown authority that the president has to send over U.S. munitions to Ukraine,” Walker said. 

“And those questions have largely been ignored because there’s seemingly a divide: You either support the packages or you don’t,” he added. “And there is no medium where you are asking what we believe are substantive and reasonable questions around this.”

The U.S. has provided more than $30 billion to Ukraine in security assistance since the February 2022 invasion. While a large majority of lawmakers in both parties have backed Ukraine aid packages, signs of fatigue are emerging with fighting expected to continue at least into 2024. 

American public support for backing Ukraine with more arms remains strong at roughly 59 percent, but support has slipped a few points since last year and is increasingly split along party lines. Republicans are much less likely to support the transfer of weapons and munitions to Ukraine than Democrats, 42 percent to 79 percent. 

And some on the far right have ramped up calls to curtail or end U.S. assistance altogether. 

Rhyan Lake, a spokesperson for the Democratic National Committee, said that while “MAGA Republicans trip over themselves to side with [Russian President Vladimir] Putin, President Biden stands on the side of democracy and alongside our allies.”

Neither the Trump campaign nor the Republican National Committee responded to requests for comment.

Biden has warned against slowing down U.S. support for Ukraine — noting it’s exactly what Russia wants.

“One year into this war, Putin no longer doubts the strength of our coalition,” Biden said in an address marking the first anniversary of the war in February.

“But he still doubts our conviction. He doubts our staying power. He doubts our continued support for Ukraine. He doubts whether NATO can remain unified,” he continued. “But there should be no doubt: Our support for Ukraine will not waver, NATO will not be divided, and we will not tire.”

GOP leaders in Congress have largely focused their concerns on whether U.S. arms are being misused or looted in Ukraine and whether U.S. military readiness is imperiled by Ukraine support, particularly should China invade Taiwan. 

But a far-right minority is taking a harder line on the war. A GOP letter to Biden released last week and signed by 19 lawmakers explicitly said their support for future aid packages hinged on a diplomatic strategy from the administration to end the war.

Trump, the leading candidate in the Republican polls by a wide margin, has also backed the idea of ending the war as soon as possible, which experts say would likely require ceding large parts of Ukraine to Russian control. 

“If it’s not solved, I will have it solved in 24 hours with [Ukrainian President Volodymyr] Zelensky and with Putin,” Trump told Fox News host Sean Hannity last month. “It’s a very easy negotiation to take place. I will have it solved within one day, a peace between them.”

DeSantis, who has not thrown his hat in the ring yet but is considered a likely 2024 candidate, also drew widespread criticism last month after he said the war in Ukraine was a “territorial dispute.”

The Florida governor later walked the comments back but made clear he believed there was no “sufficient interest” for U.S. involvement in the war. And in a recent interview with a Japanese magazine, he pushed for a cease-fire.

“It’s in everybody’s interest to try to get to a place where we can have a cease-fire,” he said, also accusing European countries of not doing enough to support Ukraine.

Ukraine has said a cease-fire is not in its best interest — a position backed by the U.S. — because it would only allow Russia to regroup and come back.

Other Republican candidates who are trailing in early polling offer a more supportive stance on the war, previewing a potentially contentious primary issue for the GOP.

Nikki Haley, the former governor of South Carolina and a former U.S. ambassador to the United Nations under Trump, waded into the fight when she called out a “weakness” among some conservative politicians on Ukraine.

“They say the U.S. shouldn’t care about Ukraine because this war isn’t our fight,” she wrote in an op-ed last month. “Some call it a mere ‘territorial dispute.’ They say we should ignore Ukraine so we can focus on China. This has it backward. China loses if Ukraine wins.”

Arkansas Gov. Asa Hutchinson, who officially announced his 2024 bid on Wednesday, has also called it a “mistake” to withdraw Ukraine support.

“I’m very much supportive of Ukraine. I believe they’re fighting a battle that helps reflect a free Europe,” he said on CNN last year.