Edging toward a vote, senators convened Saturday for a second consecutive weekend session on the bipartisan infrastructure bill, and passage of the $1 trillion package could wrap up quickly or drag on for days if opponents try to slow President Joe Biden’s big priority.

“We can get this done the easy way or the hard way,” Senate Majority Leader Chuck Schumer, D-N.Y., said as the Senate opened. He said he would keep senators in session until they finished the bill and sent it to the House.

Vice President Kamala Harris was expected to be on Capitol Hill for afternoon meetings on the legislation, which Biden said offered a potentially “historic investment,” on par with the building of the transcontinental railroad or interstate highway system. The Senate appeared on track to approve the bill, despite days of fits and starts.

At noon, senators planned to see whether they could reach a crucial 60-vote hurdle that would determine whether the tenuous alliance between Republicans and Democrats could hold on the public works package. Ten Republicans would have to join all Democrats to advance the measure past a filibuster; more votes would then follow.

Senate Republican leader Mitch McConnell of Kentucky has so far allowed the bill to progress, and his vote will be one to watch. “This is a compromise,” he said Saturday, signaling potential support.

The Infrastructure Investment and Jobs Act is a first part of Biden’s infrastructure agenda. It would inject $550 billion of new spending over the next five years on roads, bridges, waterworks, broadband and other projects to virtually every corner of the nation.