WASHINGTON Senate Republicans are in deep distress over whether to support a plan to fix the migrant crisis at the U.S.-Mexico border that includes key concessions they had demanded from Democrats months ago in exchange for approving new U.S. aid to Ukraine.

The bipartisan legislation is expected to be unveiled as early as Friday, giving senators time to review the text before a planned procedural vote next week. But with former President Donald Trump , House Speaker Mike Johnson (R-La.) and much of the right whipping opposition to the bill before it has even been unveiled, its future in the Senate appears to be in serious jeopardy.

Theres a lot of really good conservative border policy, but its become a target, Senate Minority Whip John Thune (R-S.D.) acknowledged on Thursday. If the bill is strong enough and good enough and we have a strong number of Republicans who are interested in supporting it, then we will see where it goes from there.

Republicans have for years called on President Joe Biden to address the crisis on the border, insisting that the elevated flow of migrants is an urgent national security threat and calling for legislation to address it. But with an agreement in sight after four months of negotiations, many in the GOP now say that Congress doesnt need to pass new legislation and that Biden ought to simply take executive action to fix it. Some have openly admitted they dont want to give Biden a victory ahead of the November presidential election by letting him take off the table an issue on which he rates poorly among the electorate.

Its proven to be a political liability for President Biden, so they want to try to act like theyre doing something about it for a fig leaf, Sen. John Cornyn (R-Texas), who is undecided on the bill, said of the Democrats on Thursday.

The deal would reportedly require the U.S. to close the border if a seven-day average of illegal crossings reaches or climbs past 5,000 encounters . It would also speed up the asylum process, which has long suffered from a lack of resources and an overwhelmed immigration court system.

Sen. Lisa Murkowski (R-Alaska) called out opponents of the bill for rejecting proposals to toughen border enforcement that her party had insisted on from the beginning, though few in the GOP seem to be listening.

It was the Republicans, I will remind you, that told the Democrats months ago that if you want to try to get your Ukraine funding, youre going to have to take up the border issue, Murkowski said. This is what we asked for... lets take up what we asked for.

The growing opposition within the GOP has frustrated Sen. James Lankford (R-Okla.), who has for months been engaged in painstaking talks to craft the measure alongside Sens. Chris Murphy (D-Conn.) and Kyrsten Sinema (I-Ariz.).

Lankford, who is well-liked on both sides of the aisle, said he has had conversations individually with each GOP senator and leadership in the House in an attempt to correct misinformation and internet rumors about its provisions. Trump allies have alleged all sorts of things without viewing the bill, including that it provides amnesty to undocumented immigrants, a dirty word on the right.

I feel like the guy standing in the middle of a field in a thunderstorm holding up a metal stick, Lankford said Thursday, according to PunchBowl News .

For any of my colleagues that want to do this, go do the work on it, he added. But dont just do a press conference. Actually sit down with the other side and figure out what we can actually resolve.

The bill will need at least 10 Republican votes to overcome a filibuster on the Senate floor. But it will likely need even more GOP support a majority of the Senate Republican Conference in order to have a chance of swaying the large opposition in the House.

Senate Minority Leader Mitch McConnell (R-Ky.) earlier this week appeared to open the door to the possibility of passing a standalone emergency aid package for Ukraine, Israel and Taiwan without the border provisions, but its not clear whether that would have any greater chance of success of passage in Congress. Tougher border enforcement policy was supposed to give Republicans political cover to vote for a bill that includes aid to Ukraine, but even that strategy now seems to be in doubt.

We have a bipartisan agreement to fix the border. Why on earth wouldnt we vote on that and support it now that weve gotten it done? Murphy told HuffPost on Thursday when asked to respond to McConnells comments.

Its wild to me that after working for four months to get a breakthrough deal to fix the border, Republicans are talking about walking away from it just because Donald Trump doesnt like it. Thats ridiculous.

Arthur Delaney contributed to this report.