The Senate’s marathon voting session on a $1.9 trillion coronavirus relief package was going strong early Saturday, with about a dozen amendments dispensed with and an unknown number still in the queue as of 5 a.m.

It was the second all-night “vote-a-rama” in a little over a month, after the chamber recessed at 5:38 a.m. on Feb. 4 after adopting the fiscal 2021 budget resolution that paved the way for Democrats to draft the aid bill that’s nearing passage on a party-line vote. Adoption of the budget blueprint gives lawmakers the ability to use the reconciliation process, one of the only tools available for bypassing a Senate filibuster.

The first amendment vote began just after 11 a.m. Friday, but that wasn’t gaveled to a close until almost 12 hours later as held the vote open to try to tamp down a defection by moderate Joe Manchin III, D-W.Va., over a disputed unemployment benefits amendment.

A breakthrough finally came after a long day and night of backroom bargaining that resulted in an agreement to extend a $300 weekly unemployment insurance supplement through Labor Day. That’s about a month shy of a previous compromise negotiated between the White House and moderate Democrats.

[Senate sets new mark for longest recorded vote thanks to vote-a-rama 2021]

The pact would preserve an earlier provision making the first $10,200 in unemployment benefits exempt from taxes, but not for households earning more than $150,000 a year.

“Now that this agreement has been reached, we are going to power through the rest of the process and get this bill done,” Majority Leader Charles E. Schumer announced on the Senate floor around 11 p.m. Friday. “Make no mistake: We are going to continue working until we get the job done.”

But Republicans, who oppose the aid package, were clearly irritated by the daylong impasse that delayed them from offering hundreds of amendments. Just after Schumer’s announcement, Minority Leader Mitch McConnell moved to adjourn the Senate until 10 a.m. on Saturday, although that motion was defeated in a party-line vote of 49-50.

That was after the chamber set a new record: 11 hours and 50 minutes devoted to a single floor vote. The previous record — on whether to bar U.S. strikes on Iran without congressional authorization — lasted 10 hours and 8 minutes in June 2019.

“Well my goodness,” McConnell deadpanned. “It’s been quite a start to this fast-track process.”

Manchin had been pressing for jobless benefits to be smaller, and end sooner, than many other Democrats wanted. He’s expressed concerns employers in his state won’t be able to hire enough workers as the businesses start to reopen, particularly after vaccines are distributed this spring.

In a statement, Manchin said the jobless aid agreement “enables the economy to rebound quickly while also protecting those receiving unemployment benefits from being hit with [an] unexpected tax bill next year.”

To offset some of the added cost, the compromise amendment would extend a limit on losses some business owners can claim against other income for an extra year, through 2026. The excess loss limit was imposed as part of Republicans’ 2017 tax overhaul, to help pay for a new small-business tax deduction.

White House Press Secretary Jen Psaki said in a statement that President Joe Biden “supports the compromise agreement, and is grateful to all the senators who worked so hard to reach this outcome.”

Record-breaking vote

The vote to kick things off Friday morning was on an amendment from Senate Budget Chairman Bernie Sanders, I-Vt., to add back the minimum wage increase that had to be stripped from the House version to comply with Senate rules.

Republicans raised a point of order against Sanders’ amendment, which created a 60-vote hurdle. The vote was 42-58 in favor of waiving the budget rule, falling 18 votes short. But the vote wasn’t called for hours as Democrats negotiated with Manchin.

Manchin seemed to catch fellow Democrats and the White House by surprise when he wouldn’t back the earlier unemployment proposal, offered by Thomas R. Carper, D-Del., which would have extended the $300 jobless benefits through Oct. 4, with no income cap on the unemployment tax benefit.

That led Democrats to hold the first vote of the day open for so long that it ultimately broke the modern record, continuing as lawmakers and staff scrambled to draft the amendment text and get it scored by the Congressional Budget Office.

The catalyst for the standoff was a competing proposal from Rob Portman, R-Ohio, which would have shortened the length of the unemployment benefits extension to July 18. 

Portman’s proposal also didn’t have the tax exemption for jobless aid, which he argued was unfair to workers who have to pay taxes on their income. It also didn’t have the extension of the pass-through business deduction limit, which Portman said scored as a $31 billion tax increase.

Manchin ultimately backed Portman’s amendment, which was adopted on a 50-49 vote. But the Democrats’ compromise, offered by Finance Chair Ron Wyden, D-Ore., was adopted later — also on a 50-49 vote, with Manchin’s support — superseding Portman’s earlier effort.

Wyden said the proposal amounted to an “economic lifeline for Americans who would strongly prefer to be back at work.” He questioned why Republicans, traditionally the party of tax cuts, would oppose a “modest amount of tax relief” for jobless aid beneficiaries.

The only other amendment adopted thus far was one from Maggie Hassan, D-N.H., that would require local school systems to produce a plan for reopening for in-person instruction within 30 days of receiving funds under the bill.

Hassan’s amendment was adopted, 51-48, after Democrats defeated a competing amendment from Marco Rubio, R-Fla., that would have conditioned the measure’s $125.8 billion in K-12 funds on reopening. Rubio’s amendment was rejected, 48-51. 

Hassan and Rubio are running in two of the most closely-watched Senate races next year; Inside Elections with Nathan L. Gonzales considers both to be “battleground seats” in the 2022 midterms.

Another amendment that got a majority in support wasn’t actually adopted because of budget reconciliation rules. Sen. Jon Tester, D-Mont., teamed up with Manchin and the Republicans on an amendment to force the Biden administration to approve TransCanada’s Keystone XL pipeline project.

The vote was 51-48, but because it was nongermane to the bill, 60 votes were required after Sanders raised a point of order.

Deadline approaching

The current $300 weekly benefit lapses on March 14, which is the Democrats’ self-imposed deadline for getting a bill to President Joe Biden’s desk.

The House-passed bill would renew the benefits through Aug. 29, but boost them to $400 a week.

It wasn’t immediately clear that House Democrats would be satisfied with the outcome across the Capitol.

Rep. Bonnie Watson Coleman, D-N.J., pointed out on Twitter that even before the jobless benefit reduction, Senate Democrats had ditched a provision to raise the federal minimum wage and scaled back the income threshold for receiving direct payments, resulting in 400,000 fewer New Jersey residents qualifying.

“This trend is outrageous,” Watson Coleman wrote. “What are we doing here? I’m frankly disgusted with some of my colleagues and question whether I can support this bill.”

Sen. Sherrod Brown, D-Ohio, expressed support for the package even if unemployment benefits were scaled back. Brown cited the entirety of the package, including things like emergency rental assistance, expanded tax credits for low-income households and money for schools as reasons to support it.

“I think people recognize this is a big, big deal,” Brown said. “This bill is extraordinary what we’re able to do, and if some things change at the margins, they change at the margins.”

Republicans earlier appeared to delight in the Democrats’ struggle to hold their caucus together. At a news conference and in interviews, GOP senators pointed to the challenge of trying to pass a mammoth aid package on a party-line vote in a 50-50 Senate.

“That’s why reconciliation is a bad idea,” Portman said. “They should have worked with us.”

Paul M. Krawzak, Lindsey McPherson, Jennifer Shutt and Doug Sword contributed to this report.