Read: What the president could do if he declares a state of emergency

Shelby and Leahy are among the eight Republicans and nine Democrats from the House and Senate Appropriations Committees charged with working out an agreement to fund the Department of Homeland Security, which oversees protection of the southern border. On Friday, the president signed a stopgap funding measure to end the 35-day government shutdown over his wall demands, and to fund the government through February 15. If the committee cannot reach a deal on border security that is acceptable to the president by then, another partial shutdown could happen. Alternatively, Trump has said he could declare a national emergency to unlock funding for the wall, an idea that many of his fellow Republicans, not to mention Democrats, have opposed. According to The Washington Post’s reporting, a meeting at the White House might happen on Thursday between Republican members of the committee and the president.

Trump didn’t rule out going the emergency route in an interview over the weekend with The Wall Street Journal, during which he also expressed doubt about the committee’s ability to make the deadline. “I personally think it’s less than 50-50, but you have a lot of very good people on that board,” Trump told the Journal. In a tweet on Thursday morning, he took a more dire view of the group’s prospects: “Republicans on the Homeland Security Committee are wasting their time,” Trump wrote. “Democrats, despite all of the evidence, proof and Caravans coming, are not going to give money to build the DESPERATELY needed WALL.”

Nevertheless, at the committee meeting on Wednesday afternoon, lawmakers sounded optimistic, extolling the bipartisan nature of the appropriations process and their fellow members. “There’s good people in that conference committee,” Senator Jon Tester of Montana, a moderate Democrat on the committee, told reporters. “I think we can come to an amiable conclusion if we’re left to our own device.” In her opening remarks to the group, Democratic Representative Nita Lowey of New York, the chairwoman of the House Appropriations Committee, said she was confident that the conferees would reach a compromise, citing the “proud tradition” of the two appropriations committees. “We’re setting the stage as to how the new Congress … can or cannot function,” Republican Senator Roy Blunt of Missouri said at the meeting. “This is our first real opportunity to show that we can do our job.”

But despite lawmakers’ stated eagerness to resolve the border battle, reaching a deal that satisfies all parties involved—including the president—will be as difficult as it was during the government shutdown, if not impossible. There is still a clear dissonance between the two parties’ priorities. Most of the Republicans on the committee urged in its inaugural meeting that any successful deal on border security would need to involve three components: the hiring of new personnel, investment in new technology, and as the president has required, the construction of some kind of physical barrier.