WASHINGTON (AP) — Democratic leaders have a potent dynamic on their side as Congress preps for its first votes on the party’s $1.9 trillion COVID-19 relief bill: Would any Democrat dare cast the vote that scuttles new President Joe Biden’s leadoff initiative?

Democrats’ thin 10-vote House majority leaves little room for defections in the face of solid Republican opposition, and they have none in a 50-50 Senate they control only with Vice President Kamala Harris’ tiebreaking vote. Internal Democratic disputes remain over raising the minimum wage, how much aid to funnel to struggling state and local governments and whether to extend emergency unemployment benefits another month.

Yet with the House Budget Committee advancing the 591-page package Monday, Democrats across the party’s spectrum show little indication they’re willing to embarrass Biden with a high-profile defeat a month into his presidency.

Such a setback would deal early blows to Biden, new Senate Majority Leader Chuck Schumer, D-N.Y., and California Democrat Nancy Pelosi in what could be her last term as House speaker. It could also wound congressional Democrats overall by risking repercussions in the 2022 elections if they fail to unite effectively against clear enemies like the pandemic and the frozen economy.

“You think very seriously before casting a deciding vote against your own party’s president’s legislative agenda,” said Ian Russell, a Democratic consultant. But he cautioned that lawmakers must decide “for themselves how their vote is going to play out” at home.

The issue that’s provoked the deepest divisions is a progressive-led drive to boost the federal minimum wage to $15 hourly over five years. The current $7.25 minimum took effect in 2009.

“It was the No. 1 priority for progressives,” Rep. Pramila Jayapal, D-Wash., chair of the Congressional Progressive Caucus, said in an interview last week. “This is something we’ve run on and something we’ve promised to the American people.”

An overall relief bill, including the minimum wage boost, is expected to clear the House, and likely the Senate as well. But the minimum wage boost’s fate is shaky in the Senate, where Joe Manchin of West Virginia, perhaps the chamber’s most conservative Democrat, has said $15 is too expensive. Sen. Kyrsten Sinema, D-Ariz., has suggested she might oppose it, too.

More ominously, the Senate parliamentarian is expected to rule soon on whether the minimum wage provision must be tossed from the bill.