Senate Democrats are uncertain about triggering a government shutdown over amnesty for DACA recipients, but the White House is preparing the federal government for the possibility.

White House Budget director Mick Mulvaney said that the likelihood of a government shutdown was “50-50” but that they were making preparations.

“We’re planning for it as if it’s 100 percent,” he told reporters on Friday. “That’s what we do, we run the government, and we will run the government if a bill passes, we will run the government if a bill doesn’t pass.”

White House advisor March Short told reporters at the White House on Friday that the president was working to prevent a shutdown.

“We’re trying to keep it open,” he said shortly.

A short four-week funding bill passed the house on Thursday, but Democrats aren’t sure whether or not they will support the measure.

House Speaker Paul Ryan expressed frustration at the possibility of a shutdown on Thursday.

“This is unacceptable. This is needless. This is wrong,” he told reporters in a press conference.