Washington CNN  — 

Standing alongside his Ukrainian counterpart at the White House a little more than a year ago, President Joe Biden vowed American support for Ukraine “as long as it takes.” It’s a commitment he’s long repeated in the 22 months since Russia’s unprovoked invasion.

On Tuesday, as President Volodymyr Zelensky was paying another visit to Washington under dramatically altered circumstances, Biden pledged the US would provide critical weapons and equipment “as long as we can.”

The quiet shift in language appeared to acknowledge a reality made even starker following Zelensky’s eleventh-hour appeal for more assistance: American backing for Ukraine is neither a guarantee nor an open-ended commitment. What comes next for Ukraine – a harsh winter of Russian attacks on Ukraine’s infrastructure made worse by the fading prospect of help coming from Capitol Hill – is daunting.

Biden administration officials say that both the US and Ukraine recognize that Ukraine has to change its strategy in the coming year if it wants to push the Russians further back and secure a more favorable negotiating position once the time comes for peace talks.

Ukrainian officials, including Ukrainian Defense Minister Rustem Umerov, have in recent weeks asked their US counterparts for more face time with senior US military officials, recognizing that “something has to change” in how Ukraine is waging the war against Russia, two US defense officials said.

In response, the US has decided to allow General Antonio Aguto – who currently leads a joint forces command stationed in Wiesbaden, Germany, called Security Assistance Group-Ukraine – to enter Ukraine for longer stretches of time to advise Ukrainian forces, the officials said.

Col. Martin O’Donnell, a spokesman for US Army Europe and Africa, declined to comment on Aguto’s travels. “US military officials regularly engage with the US Embassy in Kyiv and senior Ukrainian military leaders to consult on a range of issues,” he said. “However, for operations security reasons, we won’t discuss specifics related to any official travel.”

Previously, Biden administration officials were reluctant to allow senior military officials to remain in Ukraine for long periods to advise Ukrainian military officials on their campaign against Russia, wary of being perceived by Russia as pulling the strings of Ukraine’s operations, the officials explained. But the US now believes having Aguto there will be key to facilitating better intelligence sharing and war gaming between the US and Ukraine.

That partnership could help ease some of disagreements that have popped up between the US and Ukraine over how best to prosecute the war against Russia. The US wanted Ukraine to focus more on the south, believing it was strategically more important than the east. But Zelensky and his advisers did not agree.

Some US officials were frustrated that Ukraine kept delaying its counteroffensive, which allowed Russia to significantly fortify its defensive lines – an intense level of fortification the US was not anticipating when it began training the Ukrainians on combined arms and mechanized warfare, one of the officials said.

The US has discussed with Ukraine the possibility, moving forward, that the Ukrainians shift to focusing on holding the territory they already control and building it up to the point that Russia cannot forcibly take it — a so-called “hold and build” strategy, the official said.

But that is not a long-term solution, because the Russians would continue to hammer Ukrainian positions, and have the ability to refill their ranks and rearm in a way that Ukraine cannot.

Biden urges Zelensky not to lose hope

Tuesday’s visit to the American capital was a long way from what the Ukrainian leader experienced when he made his first wartime trip outside of Ukraine in December 2022.

Gone was the mostly bipartisan warmth that greeted Zelensky when he visited a year ago. Instead of standing ovations, unfurled Ukrainian flags and assurances of more weapons from Congress, Zelensky on Tuesday found himself up against a wall of opposition from Republicans, who are demanding tougher immigration rules before approving new aid.

It appeared unlikely the deadlock over immigration would be resolved by the end of the week, when Congress is set to depart for its holiday recess, though negotiators meeting Tuesday said progress was being made.

Sen. Mitch McConnell, the top Senate Republican and himself a strong backer of Ukraine, called it “practically impossible” for a package to be quickly passed.

Biden tried encouraging his Ukrainian guest during talks in the Oval Office, telling Zelensky he didn’t want him losing “hope.”

“Congress needs to pass supplemental funding for Ukraine before they break for the holiday recess, before they give Putin the greatest Christmas gift they could possibly give him,” Biden said as a fire roared behind him in the fireplace.

By then, however, it was already clear the in-person appeals Zelensky had once been so successful in leveraging over the course of the 22-month war no longer carry the weight they used to, and that his ability to move Republicans from their position is limited.

“I don’t know whether he moved the needle at all,” Sen. John Cornyn, Republican of Texas, said after an all-senators meeting in the wood-paneled Mansfield Room in the Capitol.

Even Zelensky appeared to acknowledge the reality during his joint news conference with Biden.

“They were more than positive,” he said of his meeting with Republicans, “but we know we need to separate words from results.”

Border dispute out of Zelensky’s hands

In part, that is because the issue at the heart of the impasse – tougher rules that would limit the number of migrants crossing the US southern border – is entirely out of Zelensky’s control. During talks with lawmakers, he declined to take a position on the matter.

Sen. Markwayne Mullin, an Oklahoma Republican who said he supports more aid to Ukraine if it’s tied to tougher border policy, said Zelensky did not wade into the immigration disagreements that are stymying a deal for more aid.

“We kept it at a high level,” Mullin said. “We are working through the process. And he understood it. He was very respectful.”

After Zelensky departed the Capitol, the immigration talks continued, with top negotiators meeting Homeland Security Secretary Alejandro Mayorkas to continue hashing out their differences. The two sides remained at odds over a number of proposals, including steps Democrats say are too extreme, and it remained uncertain whether congressional leaders would keep members in Washington next week to continue negotiating.

The White House has signaled to lawmakers that it’s open to expelling migrants at the US-Mexico border in addition to a series of other Republican asks like asylum limits, more deportations and expanding detention, as it tries to push forward Ukraine aid, according to two sources familiar with the matter.

Taken together, the proposals would mark a significant shift in immigration law and amount to major concessions by the White House over a delicate political issue.

The expulsion authority under discussion, which was first reported by CBS News, is similar to Title 42 – a pandemic-era measure invoked under the Trump administration that largely barred migrants from seeking asylum at the US southern border.

One of the triggers being discussed to use the authority is dependent on the number of border apprehensions, which would kick the expulsions into place, one source said.

CNN has reached out to the White House for comment on the negotiations.

In his news conference with Zelensky, Biden sought to shame Republicans into approving new assistance, arguing doing otherwise played into the Russian president’s hands and noting the host of a Russian state television program had heaped praise on Republicans for blocking passage of new Ukraine aid last week.

“If you’re being celebrated by Russian propagandists, it might be time to rethink what you’re doing,” Biden said.

Zelensky pressed for clear strategy on next phase of war

Beyond the immigration dispute, however, is the reality that Ukraine’s ability to push Russia out of its territory is coming under new scrutiny after its long-awaited counteroffensive failed to achieve its objective of retaking territory.

“We need a clear articulation of the strategy to allow Ukraine to win, and thus far their responses have been insufficient and have not provided us the clarity and the detail that we requested,” GOP House Speaker Mike Johnson said after meeting with Zelensky, an indication that even resolution of the immigration dispute won’t necessarily lead to immediate approval of the Ukraine assistance.

Some Republicans, particularly those closely aligned with former President Donald Trump, have begun to sharpen their criticism of Zelensky’s approach and now say it is inevitable Kyiv will have to cede territory to Russia eventually.

“If you look at how mismatched the militaries are, there’s really no pathway to peace that doesn’t run through some negotiation. I’m not saying that’s a good thing, I’m not saying it’s good that Russia invaded Ukraine, I’m not saying it’s good that Ukraine has to give up territory, but they have made no significant progress despite hundreds of billions of dollars of American aid,” Sen. J.D. Vance of Ohio said after emerging early from a meeting all senators held with Zelensky on Tuesday morning.

Zelensky “was honest about the fact that they have some strategic problems and some issues they have to solve,” Vance said. “I appreciate it, I don’t think it changed the nature of the conversation here in Washington.”

Zelensky called the prospect of giving up territory “insane, to be honest” in his news conference with Biden.

The lingering differences in approach made Tuesday’s visit even more critical for Zelensky, who is himself experiencing the first real strains in national unity within his own country since the war began.

Biden and fellow Democrats sought to use his presence to warn against the consequences of a Russian victory.

“Without supplemental funding, we are rapidly coming to an end of our ability to help Ukraine respond to the urgent operational demands that it has,” Biden said during his news conference. “Putin is banking on the United States failing to deliver for Ukraine. We must, we must, we must prove him wrong.”