WASHINGTON — The Democratic-controlled Senate voted Thursday to begin debate on President Joe Biden’s $1.9 trillion Covid-19 relief package in a party-line vote that sets the stage for a contentious process with Republicans.

The procedural motion passed by a vote of 51-50, with Vice President Kamala Harris breaking the tie. It came after Senate Democrats made some changes to the House-passed version, including new limits to eligibility for the $1,400 cash payments.

“It is time to tell the American people that help is on the way,” Senate Majority Leader Chuck Schumer, D-N.Y., said before the vote.

The Senate could pass the bill as early as this weekend, after debate and votes on amendments. The process was delayed after Sen. Ron Johnson, R-Wis., forced the entire 628-page bill to be read on the Senate floor on Thursday afternoon. Once passed, the House will need to vote again on the bill before it can be sent to the president.

The legislation is the product of negotiations between the Senate Democrats and Biden. The bill does not need any Republican votes to pass because Democrats are using a special budget process to bypass the filibuster.

Other changes include boosting the health care subsidies under COBRA for jobless people from 85 percent to 100 percent, and making all Covid-19 student loan relief tax-free, said a Senate Democratic aide. There’s also another $200 million for Amtrak, $510 million for homeless services under FEMA and $175 million to the Corporation for Public Broadcasting.

The Senate bill also slaps new “guardrails” on the $350 billion for state and local relief, the Democratic aide said. That provision is a leading target of Republican opposition.

The legislation also provides $8.5 billion in relief for rural health care providers. Sen. Susan Collins, Republican of Maine, has pushed for extra funding in that area.

Senate Minority Leader Mitch McConnell, R-Ky., blasted the Democratic bill as a “partisan spending spree” shortly before Thursday’s procedural vote.

Before a final vote can be taken, there will be a period of unlimited amendments, known as a vote-a-rama. Republicans say they are planning to try to put Democrats on the spot with myriad amendments, forcing them to defend politically contentious provisions in the bill. That will likely include motions to “strike” certain policies.