Speaker Mike Johnson faces the prospect of losing his slim majority, with retiring Rep. Mike Gallagher planning to vacate his House seat as soon as next month, according to sources familiar with the matter.

Gallagher confirmed his departure date as April 19 in a statement released shortly after reports surfaced. He expressed his coordination with House Republican leadership regarding the timeline and expressed confidence in Speaker Mike Johnson’s ability to appoint a new chair to oversee the Select Committee on the Chinese Communist Party.

Wisconsin law stipulates that Gallagher’s seat, situated in a predominantly conservative district, will remain vacant for the remainder of his term. His decision to leave before April 9 avoids triggering a special election.

Gallagher’s earlier announcement of non-reelection followed backlash for voting against impeaching Homeland Security Secretary Alejandro Mayorkas. Allegedly disenchanted by House proceedings after Speaker Kevin McCarthy’s removal, Gallagher’s exit presents a challenge for Johnson, who may face a vote on his leadership in the upcoming weeks.

Rep. Marjorie Taylor Greene’s motion to vacate, filed on Friday, targets Johnson’s collaboration with Democrats on a significant spending bill. However, the timing of the vote remains uncertain, as no other Republicans have declared support for Greene’s motion.

Gallagher’s premature departure adds to the concerns within the conference regarding its trajectory leading up to the November elections. Majority Leader Steve Scalise emphasized the necessity for unity, regardless of the majority size.

House lawmakers departed for a two-week recess, potentially delaying Greene’s vote until the week of April 8. Greene hinted at giving House GOP time to select a successor before proceeding with the vote, potentially aligning with Gallagher’s exit date.

If the vote occurs after April 19, Johnson’s position may become even more precarious, possibly requiring Democratic support to retain his speakership. Some Democrats have indicated willingness to table Greene’s resolution in exchange for a vote on a Ukraine aid package, a move that may incense conservatives.

Gallagher joins other retiring House Republicans, including committee chairs Patrick McHenry and Kay Granger. The departures of McHenry and Gallagher, given their relatively young ages, have piqued interest regarding their future endeavors.

Despite his early departure, Gallagher leaves behind a legacy of bipartisan achievements, notably the House’s passage of a bill targeting TikTok’s ties to the Chinese government. His leadership on national security and cyber policy issues has been widely recognized, ensuring continuity in the Select Committee on China’s work into the next session.