The US Senate broke a logjam late Friday when a centrist Democrat compromised on a key provision of the Covid relief package, setting the $1.9 trillion bill on a likely path to passage.
Democrats had struggled to keep Senator Joe Manchin's support for expanded unemployment aid in the sprawling measure, and he threatened to side with Republicans in the evenly divided chamber.
But the deal, which reduced the jobless benefits, kept Manchin on board and allowed action to resume in the Senate as it navigates toward passage of President Joe Biden's top legislative priority sometime this weekend.
Manchin, keen on more fiscal restraint than was evident in the Biden package, was flexing his political muscle, balking at an amendment that would increase weekly additional unemployment benefits from $300 to $400, and extending them through August.
It also provides for tax breaks of up to $10,200 for those receiving unemployment, but only families making less than $150,000.
Without passage of the rescue package, the benefits will expire on March 14 for millions of Americans.
"We have reached a compromise that enables the economy to rebound quickly while also protecting those receiving unemployment benefits from being hit with (an) unexpected tax bill next year," Manchin said in a statement.
Biden supports this compromise, White House press secretary Jen Psaki said.
"Most importantly, this agreement allows us to move forward on the urgently needed American Rescue Plan, with $1,400 relief checks, funding we need to finish the vaccine rollout, open our schools, help those suffering from the pandemic, and more," she said in a statement Friday evening.
With the impasse over, a lengthy amendment process known as a "vote-a-rama" was set to resume, with votes on potentially dozens of amendments filed by members of both parties.
The daunting process was likely to carry into the wee hours Saturday or beyond, especially given Friday's nine-hour delay.
"We are going to power through and finish this bill, however long it takes," Senate Majority Leader Chuck Schumer said at the start of Friday's marathon session.
Biden has heaped pressure on Democrats to clear the American Rescue Plan through Congress in the coming days, and the Manchin hurdle marked potential disaster.
Democrats are in control of a Senate that is deadlocked 50-50, so any defections within the party could kill the bill.
In the event of a tie, Vice-President Kamala Harris casts the deciding vote.
Republicans had offered their own jobless benefits alternative that they say would save $128 billion by reducing the benefits to $300 and extending them only to July.
West Virginia's Manchin, the most conservative Senate Democrat, weighed the dueling plans but eventually sided with his party's compromise.