Trump Announces Kristi Noem to Step Down as Homeland Security Secretary

President Donald Trump announced that Kristi Noem will step down as U.S. Secretary of Homeland Security at the end of March, with Sen. Markwayne Mullin, R-Oklahoma, appointed to replace her effective March 31.

Trump posted on Truth Social that Mullin will begin work as Homeland Security secretary. He thanked Noem for her service and said she will take on a new role as "Envoy of the American Hemisphere Shield," leading a new security initiative in the Western Hemisphere. Trump reportedly discussed the change with Noem on Thursday evening, according to U.S. media.

This marks the first cabinet resignation in Trump's second term. Noem's position faced challenges recently, including a deadly shooting by federal agents of two U.S. citizens during an immigration operation in Minneapolis, tensions with the U.S. Coast Guard, and her statements to lawmakers.

Lawmakers questioned Noem in Senate Judiciary Committee hearings about a $200 million ad campaign urging undocumented immigrants to leave voluntarily. The department has spent about $80 million on the ads since early 2025. Noem said Trump approved the multi-million-dollar campaign, but a White House official told NBC News that "the U.S. president did not sign the $220 million advertising campaign."

Noem drew criticism for calling the two killed citizens "domestic terrorists" and refusing to apologize. Some Republican senators, including Tom Tillis and Lisa Murkowski, called for her resignation in January.

Mullin, a former House member for a decade, joined the Senate in a 2023 special election. He confirmed speaking with Trump "recently" but declined further comment Thursday. Noem previously served as South Dakota governor, leading strict immigration enforcement including deportations and border restrictions.