WASHINGTON—The Senate passed a $3.5 trillion budget blueprint early Wednesday, the first step in an arduous process designed to allow Democrats to push through a sweeping package of education, healthcare, climate and other provisions without GOP support.

The party line vote, 50-49, came just before 4 a.m., one day after the Senate passed a roughly $1 trillion bipartisan infrastructure package. It is an initial victory for President Biden and congressional Democrats who are seeking to pass as much of their legislative agenda as possible this year, before next year’s midterm elections overtake Capitol Hill.

Senate Democrats “just took a massive step towards restoring the middle class of the 21st century,” Senate Majority Leader Chuck Schumer (D., N.Y.) said after the vote. “What we’re doing here is not easy. Democrats have labored for months to reach this point. And there are many labors to come. But I can say with absolute certainty that it will be worth doing.”

Minority Leader Mitch McConnell (R., Ky.) said the blueprint was “full of reckless taxing and spending.”

But Democrats, who have slim margins in both chambers, will face difficult choices and negotiations, as they work to transform the budget framework into detailed legislation.