The Senate worked through the night and past sunrise Saturday on Democrats’ showpiece $1.9 trillion COVID-19 relief bill after a deal between leaders and moderate Sen. Joe Manchin on emergency jobless benefits broke a logjam that had stalled the package.

The compromise, announced by Manchin, D-W.Va., and a Democratic aide late Friday and backed by President Joe Biden, cleared the way for the Senate to begin a marathon series of votes on amendments before eventual approval of the sweeping legislation. The bill then would return to the House, which was expected to give it final congressional approval and send it to Biden to sign.

Biden’s foremost legislative priority is aimed at battling the killer pandemic and nursing the economy back to health. It would provide direct payments of up to $1,400 to most Americans and money for COVID-19 vaccines and testing, aid to state and local governments, help for schools and the airline industry and subsidies for health insurance.

Shortly before midnight, the Senate began to take up a variety of amendments in rapid-fire fashion. The votes were mostly on Republican proposals virtually certain to fail but designed to force Democrats into politically awkward votes. It was unclear how long into the weekend the “vote-a-rama” would last.

By daybreak Saturday, senators had worked through more than a dozen amendments without substantially changing the overall package.

The lengthy standoff underscored the headaches confronting party leaders over the next two years — and the tensions between progressives and centrists — as they try moving their agenda through the Congress with their slender majorities.