WASHINGTON, Jan 24 - A bipartisan Senate deal to pair border enforcement measures and Ukraine aid faced potential collapse Thursday as Senate Republicans grew increasingly wary of an election-year compromise that Donald Trump, the likely Republican presidential nominee, says is “meaningless.”

Senate negotiators have been striving for weeks to finish a carefully negotiated compromise on border and immigration policy that is meant to tamp down the number of migrants who come to the U.S. border with Mexico, The Associated Press reported. But now that negotiations have dragged for weeks, election-year politics and demands from Trump are weighing it down.

At stake is a plan that both President Joe Biden and Senate Republican Leader Mitch McConnell have worked on for months to broker in hopes of cajoling Congress to approve wartime aid for Ukraine. The U.S. has run out of money to supply Ukraine, potentially leaving the country stranded without robust supplies of ammunition and missiles to fend off Russia’s invasion.

Trump on Thursday ramped up his criticism of the potential compromise, writing in two lengthy posts on his social media platform that it would be “meaningless” in terms of border security and “another Gift to the Radical Left Democrats” as Biden runs for reelection.

The former president said the Senate is better off not making a deal, even if it means the country will “close up” for a while. He did not propose alternate policy options.

In a closed-door Republican meeting on Wednesday, McConnell acknowledged the reality of Trump’s opposition, that he is the party’s likely presidential nominee and discussed other options, including potentially separating Ukraine and the border, according to two people familiar who spoke anonymously to discuss the private meeting. Punchbowl News first reported the remarks.

McConnell’s comments raised fresh doubts in the Senate about his level of commitment to the border deal, though advocates for moving forward countered that the leader’s remarks were being misinterpreted.

“We’re still working on it,” McConnell told reporters on Thursday morning.

He also reassured the conference at a Republican luncheon Thursday that he still personally supports pairing the border and Ukraine, said Sen. Mike Rounds, a South Dakota Republican.

White House spokeswoman Olivia Dalton told reporters aboard Air Force One on Thursday that the Biden administration has been working with the negotiators “in good faith,” feels that progress has been made, and hopes it will continue.

“We’re at a critical moment, and we’ve got to drive hard to get this done,” said South Dakota Sen. John Thune, the second-ranked Senate Republican. “If we can’t get there, then we’ll go to plan B.” (ap/ez)