On Thursday, with Donald Trump once again threatening a government shutdown over his demand for border-wall funding, a small faction of House Democrats published a letter excoriating Chuck Schumer for political apostasy—or, as it used to be known, bipartisan compromise. “As members of Congress who represent constituents who live and work along the U.S. southern border, we write to express our alarm and opposition to your comments that $1.6 billion for a physical wall along the border is the starting negotiating position for the Democrats,” they wrote in a letter to the Senate minority leader. Schumer’s characteristic, conciliatory position may have had a certain defensible logic earlier this year. But following the blue tidal wave in November, Schumer’s colleagues in the lower chamber are in no mood to cut a deal. “We believe the Democrats should oppose all funding for a physical wall along the U.S.-Mexico border in an FY 2019 Appropriations package,” wrote Texas Rep. Henry Cuellar, on behalf of a dozen Democrats.

Thirty minutes later, Schumer phoned Cuellar and asked him to retract his statement, insisting that he would be a tough negotiator with Trump. Cuellar declined, then turned around and recounted the entire conversation to Politico. “He says that he did not say ‘wall money,’ and he wanted me to take my letter back, and I said, ‘I can’t do that because our position is very strong.’ We don’t want this,’” Cuellar said. Other House Democrats also went on the record to oppose Schumer’s proffer. “I’ve heard it from other members, and it’s my feeling as well, that he could agree to something that basically puts those of us in sincere opposition to that wall in a bind,” said Rep. Raúl Grijalva, who also signed the letter. “There’s already $1.5 [billion from last year]. No more.”

There’s some dispute over whether Cuellar misunderstood Schumer’s position; in a previous statement, just one day earlier, the congressman praised Schumer’s position. (Congressional Democrats previously agreed to $1.6 billion for border security, though not a wall.) Nevertheless, the standoff underscores the explosive inter-party politics surrounding the wall, a monument to Trump’s exclusionary immigration policy, as Democrats begin to re-assert their incipient power during the lame-duck session. For now, there is little Democrats can do, on their own, to prevent Trump from getting the funding he wants. (The Republicans, for their part, seem resigned to siding with Trump. “I’m trying to get it to $5 billion,” said Republican Senator Richard Shelby.) But as House Democrats eagerly eye the clock, counting down the days until they become the majority on January 20, they are also beginning to reconsider what strategy and tactics their “resistance” should pursue, given the demands of their base and their responsibilities as legislators.

Negotiations over the shutdown will likely be delayed by the passing of George H.W. Bush, who will lie in state at the U.S. Capitol for several days, effectively preventing much legislative work from being done. Upon his death, lawmakers submitted a stopgap proposal to push back the shutdown deadline in order to mourn the former president, which Trump has indicated he would support. But that grace period won’t last long. The fissures running through the Democratic Party will have to be addressed.

Presumptive House Speaker Nancy Pelosi has masterfully suppressed the dissent in her ranks, dangling plum committee assignments to placate her critics, promising to support progressive bills, and ruthlessly dispatching with potential political threats. But Schumer, who represents the last Democratic gatekeeper before bills reach Trump’s desk, faces a more difficult task. While Pelosi will preside over a new slate of investigatory powers, channeling a progressive grassroots that wants to see heads roll, Schumer represents a caucus that, for a variety of electoral and geographic reasons, is less daring. Whereas Pelosi gained 40 seats in her chamber, Schumer lost two.