WASHINGTON (AP) — Rep. Mike Gallagher, a Wisconsin Republican who has spearheaded House pushback against the Chinese government, said Friday he would resign from the House.

Gallagher, age 40, said 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 last year 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.”