Senior Senate Republicans are furious that Donald Trump may have killed an emerging bipartisan deal over the southern border, depriving them of a key legislative achievement on a pressing national priority and offering a preview of what's to come with Trump as their likely presidential nominee. In recent weeks, Trump has been lobbying Republicans both in private conversations and in public statements on social media to oppose the border compromise being delicately hashed out in the Senate, according to GOP sources familiar with the conversations – in part because he wants to campaign on the issue this November and doesn't want President Joe Biden to score a victory in an area where he is politically vulnerable. Senate GOP Leader Mitch McConnell acknowledged in a private meeting on Wednesday that Trump's animosity toward the yet-to-be-released border deal puts Republicans in a serious bind as they try to move forward on the already complex issue. For weeks, Republicans have been warning that Trump's opposition could blow up the bipartisan proposal, but the admission from McConnell was particularly striking, given he has been a chief advocate for a border-Ukraine package. Now, Republicans on Capitol Hill are grappling with the reality that most in the GOP are loathe to do anything that is seen as potentially undermining the former president. And the prospects of a deal being scuttled before it has even been finalized has sparked tensions and confusion in the Senate GOP as they try to figure out if, and how, to proceed – even as McConnell made clear during party lunches Thursday that he remains firmly behind the effort to strike a deal, according to attendees. "I think the border is a very important issue for Donald Trump. And the fact that he would communicate to Republican senators and congresspeople that he doesn't want us to solve the border problem because he wants to blame Biden for it is ... really appalling," said GOP Sen. Mitt Romney of Utah, who has been an outspoken critic of Trump. He added, "But the reality is that, that we have a crisis at the border, the American people are suffering as a result of what's happening at the border. And someone running for president not to try and get the problem solved. as opposed to saying, 'hey, save that problem. Don't solve it. Let me take credit for solving it later.'" GOP Sen. Todd Young of Indiana called any efforts to disrupt the ongoing negotiations "tragic" and said: "I hope no one is trying to take this away for campaign purposes." "I would encourage (chief Senate GOP negotiator) James Lankford and other conservatives to produce a work product with which they will shortly allow conservatives like myself to review it and take heart that there are a number of us who won't be looking to third parties and assessing the propriety of passing this bipartisan proposal," Young said. It's an all-too-familiar dynamic for the Republicans who served while Trump was in office, where he could easily derail legislative action on Capitol Hill with the blast of a single tweet or stir up a new controversy that Republicans were forced to respond to. And with Trump now marching toward the presidential nomination, Republicans are once again bracing for life with him as the nominee. Underscoring just how damaging Trump's comments and campaign to kill the border deal have been in the Senate, one GOP senator on condition of background told CNN that without Trump, this deal would have had overwhelming support within the conference. "This proposal would have had almost unanimous Republican support if it weren't for Donald Trump," the Republican senator said. GOP Sen. Thom Tillis of North Carolina – who has also been involved in the talks – said he didn't know if anyone could convince Trump to not kill the deal. But he acknowledged that it would take some "courage" for members to be able to press ahead at this point in defiance of Trump – though Tillis argued it would ultimately be beneficial for Trump for them to pass a border security deal and help address the flow of migrants trying to enter the country. "I think this is when members of the Senate have to show some courage and do something that at the end of the day will be very helpful for President Trump," Tillis said. Asked whether it was a mistake for Trump to be assailing this deal, Tillis said: "I'll leave it to him to figure out how he needs to get into office. I hope you'll leave it to some of us who would support that effort to give him the tools he needs to really manage the border and the abuse and the dangerous situation we have today." For his part, McConnell – who has had zero relationship with Trump since the January 6, 2021, Capitol attack – downplayed Trump's opposition saying, "It's not anything new," and insisting they were not abandoning the talks. "We're still working," McConnell said. "Trying to get an outcome." Sen. John Thune, the no. 2 Senate Republican, said the discussions have reached a critical moment but acknowledged they may need to turn to a "plan B." "If we can't get there, then we'll go to plan B," Thune said. "But I think for now at least, there are still attempts being made to try and reach a conclusion that would satisfy a lot of Republicans." In the latest sign that the emerging border deal faces an uphill climb, a senior leadership aide to House GOP Leader Steve Scalise told a group of Senate Republican chiefs of staff on Thursday that it was dead on arrival in the House, according to a source familiar. Senate Republicans on the fence about the proposal may be less inclined to back it, knowing it's going nowhere in the House and knowing Trump wants a border deal killed. Frustration reigned inside the Senate GOP on Thursday amid lingering confusion over the status of a deal. While McConnell has said the talks are still proceeding, Young warned Republican leadership against pulling the plug before they've taken a thorough temperature check inside the conference, where a contingent of Republicans are still fighting for a deal. "I think leadership needs to count noses before they make any impulsive decisions," he said. Pressed on whether it was realistic to pass a border deal with Trump opposing it, Young said: "It may be possible. Listen, I'm very much attuned to the political realities, but I think before you make these consequential decisions on behalf of this conference, you've got to consult with the conference." Sen. Ron Johnson of Wisconsin, who has been openly critical of McConnell, said he was "puzzled" by the leader's comments during the closed-door meeting on Wednesday, which was supposed to be focused on Ukraine. "I mean, we were talking about funding for Ukraine and all of the sudden he brings up the border and then, again, lays out what I consider a pretty lame excuse, trying to shift blame to President Trump for, I would say, his failed negotiation, not James Lankford," Johnson said. "James Lankford has worked his tail off. It's McConnell that took away the leverage by not tying Ukraine funding to actually securing the border." Republican Sen. Lisa Murkowski of Alaska, who has made no secret of her frustration with Trump over the years, said members need to remember how big this moment is for the border and for Ukraine and put their own politics aside. "I'm not giving up. This is not about Trump and this is not about me. This is about our country. This is about democracy around the world. This is about security for our own country and so let's keep pushing to get this border deal," she said. "Let's stand by the commitments that we have made for our friends and our allies so that our word actually means something." This is the second time in six years Trump killed or was actively trying to kill a bipartisan immigration deal as it emerged. Back in 2018, Murkowski was part of bipartisan talks over the Deferred Action for Childhood Arrivals program. The bill got 54 votes in the Senate, but not enough to get it over the finish line. Sen. Chris Murphy of Connecticut, one of the Democrats involved in the border talks, expressed frustration about Trump seeking to inject chaos into the situation. "I think over the next 24 to 48 hours, they are going to make a decision as to whether they want to do this, or whether the forces surrounding Donald Trump – who want to keep chaos at the border – win," Murphy said. "So they have a decision to make. I hope they make that decision very quickly. We have an agreement that is 95% written and is ready to get to the floor if Republicans decide that they actually want to solve the problem." — CNN