WASHINGTON — The daunting effort to salvage the Republican Party’s governing agenda has fallen suddenly and squarely on the shoulders of one man: Mitch McConnell.

After the party’s humiliating health-care defeat in the House last week, the Senate majority leader is under heavy pressure to put President Trump’s to-do list back on track by confirming his Supreme Court nominee and averting a late-April federal government shutdown – all in the face of growing Democratic resistance.

While House Speaker Paul D. Ryan, R-Wis., struggled as the chief advocate of the health-care bill primarily because of Republican recalcitrance, McConnell’s challenge is different yet no less challenging: persuading enough Democrats not to obstruct the plans of an increasingly unpopular president.

“We’ve got a lot of work to do,” Sen. John McCain, R-Ariz., said. “And one of the things we need to do – and it’s going to be harder now because we just failed – is there’s got to be bipartisanship.”

Hunger for a win and the belief that ambitious goals are still achievable are fueling McConnell, R-Ky., and his team. But dim prospects for cooperation in the upper chamber, where Republicans control 52 seats, have forced him to ponder extreme measures, including a rule change known by insiders as the “nuclear option” that would allow Judge Neil Gorsuch to be seated on the Supreme Court with a simple majority vote.

Such a move would likely enrage Democrats heading into a fight over funding the government, when McConnell will once against need the support of his Democratic colleagues to avert a government shutdown that would begin April 29 if Congress fails to pass a stopgap bill. Democrats have already threatened to thwart the measure – again by requiring a 60-vote procedural hurdle to be cleared – if it includes any money for a U.S.-Mexico border wall.

“Do they really think history books or the American people will look kindly on them for filibustering this amazingly well-qualified and widely-respected nominee?” McConnell asked in a floor speech Wednesday, in an effort to shift to burden to Democrats.

The minority party has considerably more leverage in the Senate than in the House, making McConnell’s task as critical as it is challenging. It also creates a moment of reckoning for the six-term senator’s leadership – and national profile.

McConnell, 75, has struck major agreements with Democrats in the past, notably then-Vice President Joe Biden, a longtime Senate colleague with whom he negotiated a deal in 2012 to avert deep cuts and tax increases known as the “fiscal cliff.”

But he has also been blamed for leading Republican obstruction on many occasions, including last year, when he blocked hearings for Judge Merrick Garland, then-President Barack Obama’s choice for the current Supreme Court vacancy.

Now McConnell’s task is to bring the chamber together.

McConnell’s most immediate priority is Gorsuch, whose fate will be decided solely by the Senate. The Kentucky Republican has made clear that he is deeply invested in that battle, publicly guaranteeing that the federal appeals judge who has won large-scale praise in the GOP will be confirmed by the end of next week.

He added that it will be “up to” his Democratic colleagues “how the process to confirm Judge Gorsuch goes forward.”

A similar pattern has emerged in negotiations over a must-pass, stopgap funding bill to fund the government beyond April 28. Democrats have signaled they will block any attempts to include money for a wall along the Mexican border, one of Trump’s key campaign promises and now a top administration priority.

It remains to be seen how effective a dealmaker McConnell can be in the current Senate, with Democrats firmly united against Trump. Some Democrats argue that McConnell, through his resistance of Obama’s agenda, is partly culpable for the toxic relations in the chamber.

“There are a lot of issues where we can work together, if they are willing to truly be open to Democratic proposals,” Sen. Richard Blumenthal, D-Conn., said.