Rep. Matt Gaetz on Monday moved to oust Speaker Kevin McCarthy from the top House leadership post, offering a motion to vacate the chair on the House floor – a rare procedural move that can be used to force a vote to remove the speaker.

It’s not yet clear how the challenge to McCarthy will play out, but the effort represents the most serious threat to his speakership to date. A floor vote to oust McCarthy would require a majority to succeed.

“Bring it on,” the California Republican wrote on X shortly after the motion. Gaetz responded to the post with one of his own, writing, “Just did.”

The move marks a major escalation in tensions for a House GOP conference that has been mired in in-fighting and could be thrown into chaos if McCarthy is pushed out of the speakership. It comes as a bloc of House conservatives have continued to thwart McCarthy, voting against key priorities of GOP leadership and repeatedly throwing up roadblocks to the speaker’s agenda.