Looming over Senate Democrats this year is a decision that could fundamentally change Congress: whether to change or eliminate the rules of the filibuster to enact President Joe Biden’s agenda. Liberal advocates have pushed hard for the change, urging the Senate to modify or eliminate rules that now require a vote by 60 of the 100 senators to advance most bills. Many Democrats are on board, arguing that Republicans are determined to block almost every one of their priorities in the 50-50 Senate even though Democrats hold Congress and the presidency. But others in the party are wary, fearing it will end bipartisanship in the Senate.

Yet most of the skeptical Democratic senators say they are ultimately open to some changes to the rules if Republicans won’t negotiate on their major policy goals, particularly legislation — filibustered by Republicans just last week — that would overhaul elections and make it easier to vote.

The two biggest Democratic obstacles to filibuster changes, for now, are Sens. Joe Manchin of West Virginia and Kyrsten Sinema of Arizona. Both have reiterated their opposition in recent weeks. A simple majority can change the Senate’s rules, but getting all 50 Democrats to agree could prove difficult.