WASHINGTON ― Senate Democrats are, by and large, united in filibustering Supreme Court nominee Neil Gorsuch. On Monday, they hit the 41 votes they needed to block Gorsuch’s nomination.

But a handful of Democrats are siding with Republicans and planning to vote to end the filibuster. That’s because of what Republicans are signaling they’ll do in retaliation for Democrats filibustering President Donald Trump’s court pick: use a rare procedural maneuver to change the Senate rules so it only takes 51 votes, versus 60, to advance a Supreme Court nominee. That’s a prospect that’s bumming out senators in both parties who love their institution and its rules.

There are currently 52 Republicans and 48 Democrats (including two independents who caucus with them). That means that Republicans, if they do change the rules, could confirm Gorsuch without any Democratic votes. The rule change would also mean the Senate becomes more partisan at a time when it’s already incredibly divided along party lines.

Here’s where every Democrat stands on joining the filibuster against Gorsuch.

JOINING FILIBUSTER (44)

Sen. Tammy Baldwin (Wis.)

Sen. Richard Blumenthal (Conn.)

Sen. Cory Booker (N.J.)

Sen. Sherrod Brown (Ohio)

Sen. Maria Cantwell (Wash.)

Sen. Ben Cardin (Md.)

Sen. Tom Carper (Del.)

Sen. Bob Casey (Pa.)

Sen. Chris Coons (Del.)

Sen. Catherine Cortez Masto (Nev.)

Sen. Tammy Duckworth (Ill.)

Sen. Dick Durbin (Ill.)

Sen. Dianne Feinstein (Calif.)

Sen. Al Franken (Minn.)

Sen. Kirsten Gillibrand (N.Y.)

Sen. Kamala Harris (Calif.)

Sen. Maggie Hassan (N.H.)

Sen. Martin Heinrich (N.M.)

Sen. Mazie Hirono (Hawaii)

Sen. Tim Kaine (Va.)

Sen. Angus King (I-Maine)

Sen. Amy Klobuchar (Minn.)

Sen. Patrick Leahy (Vt.)

Sen. Ed Markey (Mass.)

Sen. Claire McCaskill (Mo.)

Sen. Jeff Merkley (Ore.)

Sen. Bob Menendez (N.J.)

Sen. Chris Murphy (Conn.)

Sen. Patty Murray (Wash.)

Sen. Bill Nelson (Fla.)

Sen. Gary Peters (Mich.)

Sen. Jack Reed (R.I.)

Sen. Bernie Sanders (I-Vt.)

Sen. Brian Schatz (Hawaii)

Sen. Chuck Schumer (N.Y.)

Sen. Jeanne Shaheen (N.H.)

Sen. Debbie Stabenow (Mich.)

Sen. Jon Tester (Mont.)

Sen. Tom Udall (N.M.)

Sen. Chris Van Hollen (Md.)

Sen. Mark Warner (Va.)

Sen. Elizabeth Warren (Mass.)

Sen. Sheldon Whitehouse (R.I.)

Sen. Ron Wyden (Ore.)

VOTING WITH REPUBLICANS TO END FILIBUSTER (4)

Sen. Michael Bennet (Colo.)

Sen. Joe Donnelly (Ind.)

Sen. Heidi Heitkamp (N.D.)

Sen. Joe Manchin (W.Va.)