Donald Trump helped kill Congress’ last big bid for an immigration compromise. As the Senate closes in on its next attempt, members of both parties are prepared for the former president to try it again.

Speaker Mike Johnson’s televised acknowledgement that he’s consulting with Trump on border policy is giving déjà vu to senators who witnessed the Trump administration’s 2018 squashing of a plan to pair border security provisions with help for undocumented immigrants. This time around, the Senate is on the verge of a different deal — linking border and immigration restrictions with Ukraine aid — while Trump’s influence in the GOP is peaking again.

“I hope he will dissuade people” from supporting any bipartisan border plan that emerges this year, said Sen. Josh Hawley (R-Mo.). “Can he? I don’t know… Maybe. Maybe not.”

Now that he’s won the Iowa caucus and is barreling toward the GOP nomination, Trump has reason to feel emboldened about his ability to sway congressional Republicans. If Trump goes all-out against the emerging border-Ukraine compromise, it’s even harder to imagine that Johnson would go along — and GOP senators might start peeling off into the no camp, too.

Trump appeared to begin making his stance clear on Thursday, posting on social media that he does “not think we should do a Border Deal, at all, unless we get EVERYTHING needed to shut down the INVASION of Millions & Millions of people.” Conservative Fox News host Laura Ingraham said on Wednesday night that the former president opposes an emerging Senate deal and wants Johnson to come out against it too.

“It’s certainly not helpful,” Senate Minority Whip John Thune (R-S.D.) said of Trump’s potential opposition. “But in the end, people are going to have to do what they think is right.”

About six years ago, a bipartisan group of senators hashed out a significant border security deal that would have also protected hundreds of thousands of young immigrants from deportation. At that time, Trump and Senate GOP leader Mitch McConnell were aligned on defeating the legislation, which went down on the floor. This time, however, McConnell is pushing back against Johnson and Trump’s resistance.

Sen. Mike Rounds (R-S.D.), a lead sponsor of the 2018 border legislation, readily remembers the vote total (54) that brought down that immigration measure. It fell short of the 60 votes needed to break a filibuster even as Republicans held the House, Senate and White House. And Senate Republican leaders are now trying to remind Trump that if he wins back the presidency, he won’t get the sort of concessions that Democrats are considering now.

Rounds said in an interview that some Senate Republicans are working behind the scenes to get Trump on board with this year’s legislation, telling him it would help future presidents: “Whether he believes that or not, I don’t know. But I do.”

“Anytime you have a Republican frontrunner for the presidency, people will listen to what he’s got to say. But there’s a lot of really good logic involved in trying to get something done now,” Rounds added. “That would be helpful for this administration, but absolutely necessary for the next administration.”

The trio of senators working on this year’s immigration compromise have not yet clinched a deal, but their agreement would likely strengthen asylum standards, give the government new expulsion authorities for migrants and potentially curb presidential parole powers.

It would not include a path to citizenship for young, undocumented immigrants; for that and other reasons, it’s a far more conservative template than the 2018 bill. Instead, it would ride alongside a massive foreign aid bill that many Republicans also support.

“It was very different. There’s no path to citizenship in the bill. This isn’t about immigration, this is about border security. It’s a very, very different bill,” said Sen. Thom Tillis (R-N.C.), who opposed the 2018 legislation but was involved in the talks that produced it.

Sen. James Lankford (R-Okla.) was also in the room for those 2018 immigration talks and is now the lead negotiator on a Ukraine-border deal. Lankford has not endorsed Trump yet, though several of the former president’s backers for 2024 are in favor of a deal, including Sens. Lindsey Graham (R-S.C.) and Roger Wicker (R-Miss.).

Senate Majority Whip Dick Durbin (D-Ill.) said he hopes Trump wouldn’t be able to tank the bill: “I think there are enough people like Lindsey Graham — who apparently are supporting it — that should help.”

Lankford said he did not read Trump’s comments as fatal, or even that critical.

“He was just saying we need to be able to fix everything,” Lankford said. “I don’t take it as adamantly opposed to this.”

Even if Trump does come out against the legislation, nine or more GOP senators could still shrug off his opposition. McConnell and Trump do not speak, and for now — with McConnell singularly focused on passing the agreement — it appears that the emerging deal could pass the Senate.

But senators want a bigger vote total to put pressure on the House, where the situation is much dicier. Few House Republicans supported the Senate’s recent bipartisan compromises on infrastructure, gun safety and same-sex marriage. Because Johnson faces regular threats to his speakership from the right, he’ll need broad GOP buy-in to call a vote on the Senate’s plan.

“That makes it harder,” said Sen. Mitt Romney (R-Utah.). “President Trump obviously has a big influence in our party, and on some people more than others.”

But, Romney added, “we need to do something rather than to do nothing.”