A sweeping bipartisan infrastructure agreement reached after what felt like glacially paced negotiations is now moving at a similar pace toward a likely Senate passage.

The latest procedural step came Sunday night when the Senate voted 69-28 to adopt the substitute amendment, which contains the language adopted by a bipartisan group that at most included 22 senators. The Senate then voted 68-29 on cloture on the bill.

As the Senate heads toward a passage vote, one Republican signed onto the bill while another fell away.

Sen. Todd Young, R-Ind., who had been in the group of negotiators, said he will now oppose the bill, saying “we can’t afford to continue to grow the national debt at this pace, particularly as our economy recovers from the pandemic.” He said he’s concerned about the pay-fors in the bill. Young is up for re-election next year.

Another Republican, however, said he’d back the bill. Sen. Roger Wicker of Mississippi, who has voted against prior procedural motions for the bill, announced his support on the Senate floor. Wicker is the ranking Republican on the Senate Commerce, Science and Transportation Committee.

“The bill we are now debating is far from perfect,” Wicker said. “But at the end of the day, I believe this package will do a great service for the United States and a great service for my home state of Mississippi.”

The Senate had initially tried to speed up passage of the measure, which includes $550 billion in new spending. But by Sunday, they seemed resolved that it would take until Tuesday to pass.

“We’ve lost the weekend,” said negotiator Mitt Romney, R-Utah, Sunday afternoon. “So at this stage, people are resigned to whatever time it takes.”

Senators were indeed resigned, and possibly a little irritated: they hoped to finish the bill first on Thursday, then Saturday, but were thwarted both times by Sen. Bill Hagerty, a freshman Tennessee Republican. He refused to agree to shorten the 30 hours of debate on the substitute amendment and on the final bill.

Hagerty opposes speeding up the process because of a Congressional Budget Office score finding that the bill would increase the deficit by about $256 billion.

Irked by Hagerty’s insistence on taking up the entire time for debate, Democrats have refused to agree to take up amendments.

Early Sunday, Hagerty introduced a motion to bring up 20 amendments under unanimous consent. It was immediately rejected by Sen. Kyrsten Sinema, D-Ariz., the lead Democratic negotiator on the bill, who said Democrats weren’t inclined to allow amendments if Hagerty wasn’t willing to agree to shorten the 30-hour post-cloture time.

“As the senator from Tennessee made clear yesterday in his remarks on the floor, he has declined to provide unanimous consent for a time agreement moving forward in this post-cloture time period,” Sinema said. “I’m sure it will then come as no surprise to him that there are senators on both sides of the aisle who object to unanimous consent on one or more of the amendments listed in his proposed list today. I’m sure that he offers the same level of respect to those senators … as has been offered to him as well.”

Democratic intent?

Hagerty responded that he never objected to consideration of amendments to the bill and said the objection to his request “exposes the Democrats’ true intention … to rush this bill through so they can hurry up and light the fuse on their $3.5 trillion spending spree.”

Romney early Sunday said he had hoped there’d be an agreement for further amendments — the Senate has considered 22 to the bill to date — “but that may or may not happen.”

“The power of individual senators to block votes is quite substantial, so I can’t tell you what will happen,” he said.

Senators have been trying to negotiate on amendments that would change the bill’s cryptocurrency regulations, add $50 billion to Defense infrastructure, and give states and localities the right to repurpose some of their COVID-19 relief dollars for infrastructure.

While it’s not too late for the Senate to take up amendments if all senators agree, the window appears to be closing.

“Democrats are ready and willing to vote on additional amendments to the bill before moving to final passage,” said Majority Leader Charles E. Schumer, D-N.Y. on Sunday. “That will require the cooperation of our Republican colleagues. I hope they will cooperate so we can move more quickly.”

Republican negotiators, meanwhile, defended the bill from what they called disinformation, with Sen. Bill Cassidy, R-La., sending out a series of tweets defending the bill from conservative attacks including some from former President Donald Trump.

Trump on Saturday criticized a provision in the bill that would create a pilot program for a user fee to pay for highways based on vehicle miles traveled. Though Trump had praised a similar program in Oregon during his presidency in 2018, he blasted it in a statement, saying, “they track your driving so they can tax you…they want to track you everywhere you go and watch everything you do!”

“There is no mileage tax in this bill,” Cassidy replied in one of several tweets aiming to address misconceptions about the bill. “What you are hearing is about a study to figure out if such a fee would even be possible for issues like electric cars driving on our streets without paying the gas tax like the rest of us.”

After the Senate finishes the bipartisan bill, it is scheduled to take up a budget resolution before recessing for the remainder of the month, pushing the conclusion of their work well into this week.

The bipartisan bill’s future is unclear in the House, where Speaker Nancy Pelosi has vowed to hold off on bringing it up until after the Senate passes a budget reconciliation bill that includes President Joe Biden’s more partisan domestic priorities. House moderates, however, are pushing back against that strategy, urging her to take up the bill more quickly.