Despite Republican efforts to delay and alter passage of the latest round of COVID-19 stimulus, Sen. Ed Markey told Boston Public Radio on Friday he believes the bill will ultimately become law.

"Republicans are going to be making, they're saying about 50 amendments to try and water down the relief package," he said. "There may be some adjustments at the margins, but essentially, the $1.9 trillion package will have the votes."

"Every time [Vice President] Kamala Harris votes, we win," he said, alluding to the fact that no Republican senator has voiced support for the bill.

Republican Sen. Ron Johnson forced a full reading of the 628-page bill this week, which delayed the vote. Now, senators will hear amendments, which will extend the vote into the weekend.

"I am going to be staying up overnight tonight, into tomorrow morning, it's going to be a long day's journey," he said. "We call it a vote-a-thon, that's just vote after vote on issue after issue, so [Republicans] can on the record say 'This is too much money being spent on cities and towns, too much on making sure the schools get the funding they need, too much to be spent."

Some adjustments to the bill have already been made in order to maintain support among moderate Democrats, like removing the proposal to raise the minimum wage to $15 an hour. Another compromise in the works on Friday involved lowering the unemployment benefits from $400 a week to $300.

"I would oppose that," said Markey. "I think we have to have $400 dollars, I think we should be generous through the end of August. Hopefully by Labor Day we're on the other side of this crisis and the unemployment rate is low ... I hope all the Democrats stick together on that, I think it's necessary help we give to people."

After Markey spoke with Boston Public Radio, however, Democrats conceded on that issue, and agreed to lower the unemployment benefits to $300 a week, according to Forbes.

This relief package requires only 50 votes — and a tie-breaker from Harris — to pass because it is being negotiated through a process called reconciliation, generally reserved for budgetary issues. Pressure is growing to remove the filibuster, which allows a senator to block a bill by refusing to yield the floor unless at least 60 senators overrule the speaker. Markey said once Democrats get through this COVID-19 relief bill process, they will need to figure out how to get laws passed, because Republicans have not indicated they will support any measures.

"Everything else is going to require 60 votes, and Republicans won't give them to us, even though we just had an election in 2020 that repudiated the Trump ideology," he said. "While the votes aren't there yet to repeal the filibuster, as each one of these issues passes out of the House, is sent over to the Senate, and Republicans block it, we will reach a moment where labor, educators, minority groups ... gun safety advocates, are all going to be coming together. At that moment, we will have the votes to repeal the filibuster."

Markey also discussed the Senate hearings on the Jan. 6 insurrection on the Capitol, and called for a "9/11-like commission" to fully examine what the president and his team knew about the planned attack, and when.