With about a day left to negotiate a deal to keep the federal government open, Sen. Jeff Flake (R-AZ) on Thursday night signaled that he will not back Republicans’ current plan to temporarily fund the government.

Flake joins a couple of other Republicans and the Democratic caucus in the Senate in opposing the bill passed by the House Thursday night, increasing the threat that the government will shut down on Friday night. Flake, an outspoken Trump critic who is not seeking re-election in 2018, did not pledge outright that he would oppose the bill, but told reporters he was “not inclined” to back the deal. He said that he would prefer passing a spending bill to fund the government for just a few days, a proposal pitched by the Democrats, in order to give Congress more time to finalize a deal to restore the protections in the Deferred Action for Childhood Arrivals program.

In an interview with the Daily Beast Thursday night, Flake complained that leaders in Congress were giving President Donald Trump too much power in steering negotiations on DACA. He argued that since Trump seems to constantly change his mind on what kind of deal he would back, Congress just needs to negotiate on its own and see if Trump will sign the bill.

“We’re not going to get any better, particularly on the [immigration] issue, by waiting three weeks,” Flake told The Daily Beast. “It just gives the White House time to agree, disagree, and go back and forth. We just need to pass a bill and put it either on the president’s desk… or just pass a Senate bill and see what the House does with it.”

“There’s an institutional prerogative here. We pass legislation. The president either signs it or vetoes it. We shouldn’t be beholden to everything the president wants,” the senator added. “Obviously you take that into account, but you can’t just wait. Particularly when the White House has been going back and forth and back and forth for a long time now.”

Flake is not the only Republican in the Senate who has threatened to buck GOP leaders on the House spending deal, which would fund the federal government for another month and fund the Children’s Health Insurance Program for six years. Sen. Lindsey Graham (R-SC) and Sen. Rand Paul (R-KY) have also signaled they may oppose the spending deal.