By Stephen Groves, AP

WASHINGTON (AP) — Rep. Mike Gallagher, a Wisconsin Republican who has spearheaded House pushback against the Chinese government, said March 22 he would resign from the House, leaving House Republicans with the thinnest of majorities.

Gallagher, age 40, announced he would resign his position on April 19. It will leave Republicans with a 217-213 majority in the House, meaning that they cannot afford to lose more than one vote on a party-line vote. The thin majority has already proved to be a challenge for Republican leadership and forced House Speaker Mike Johnson to work with Democrats to pass practically any legislation.

Gallagher had already announced he would not seek reelection.

A former Marine who grew up in Green Bay, he has represented northeastern Wisconsin in Congress since 2017. He spent 2023 leading a new House committee dedicated to countering China. During the committee’s first hearing, he framed the competition between the U.S. and China as “an existential struggle over what life will look like in the 21st century.”

Gallagher said in a statement, “I’ve worked closely with House Republican leadership on this timeline and look forward to seeing Speaker Johnson appoint a new chair to carry out the important mission of the Select Committee on the Chinese Communist Party.”

There also won’t be a special election for Gallagher’s seat. His resignation will happen within a window in Wisconsin law that dictates the seat be filled in the general election.

A Republican state senator, Andre Jacque of De Pere, and a former state senator, Roger Roth, are running for the Wisconsin 8th Congressional District seat that is being vacated.

The district is solidly Republican, but the Wisconsin Democratic Party said in a statement that it would be “fighting hard” for the seat and called Gallagher’s resignation “a remarkable indictment of a do-nothing GOP majority obsessed with creating chaos.”

For a time, Gallagher was seen as a rising star in the GOP and was one of the highest-profile Republicans considering a run for U.S. Senate this year against incumbent Wisconsin Democrat Tammy Baldwin. But he abandoned the idea in June. He said then that he wanted to focus on countering China through the committee and that he planned to run for a fifth term in the House.

Gallagher led the successful push this month to pass in the House a bill that would lead to a nationwide ban of the popular video app TikTok if its China-based owner doesn’t sell its stake. He, along with a wide bipartisan contingent, argued that the company’s current ownership represented a national security threat.

But Gallagher found himself at odds both with former President Donald Trump and his supporters. He also angered fellow Republicans in February by refusing to impeach Homeland Security Secretary Alejandro Mayorkas.

The GOP was looking to oust Mayorkas as a way to punish the Biden administration over its handling of the U.S.-Mexico border, but the House’s first impeachment attempt fell just one vote short in February after Gallagher and two other Republicans refused to support the action. They argued that Republicans were misusing impeachment.

Still, GOP members surrounded Gallagher on the House floor in an attempt to change his mind, but he refused to change his vote. Republicans were eventually able to impeach Mayorkas when other lawmakers returned from absences. But just days after the first failed impeachment vote, Gallagher announced he would leave the House.

Associated Press writers Scott Bauer and Todd Richmond in Madison contributed.