Now Democrats are in sharp disagreement over core elements of the next agenda items — on infrastructure, climate change and immigration — both on key policy areas as well as whether Congress should begin to pay attention to the eye-popping federal budget deficit, as a growing number of moderate Democrats want.

Plus, the House has already passed an array of bills that Democrats have long campaigned on: expanding background checks on firearms sales, making it easier to unionize and expanding access to voting. But all those measures stand little chance of clearing the 60 votes needed to advance legislation in the Senate — unless Democrats in that body gut the filibuster, an issue already badly dividing their party as progressives lack the votes to make fundamental changes to the slow-moving institution.

Rep. Gerry Connolly, a veteran Virginia Democrat, predicted “frustration in our future” because of the rules of the Senate.

“I think there’s a real risk of political letdown because expectations are relatively high,” Connolly said. “If the reason you’re not getting things through is because of this archaic, racist-laden procedure that requires a super-majority 60 votes to pass something, I don’t think that’s going to fly in today’s environment, and, frankly, nor should it.”