President Trump fired Homeland Security Secretary Kristi Noem on March 5, 2026, and announced Oklahoma Senator Markwayne Mullin as her replacement, effective March 31. The dismissal was confirmed by both NPR and Fox News. Noem's removal came after back-to-back congressional hearings in which she faced pushback from Republican senators over her claim that Trump personally approved a $220 million taxpayer-funded advertising campaign for DHS immigration enforcement messaging.

Trump announced the change on Truth Social, writing that Mullin "will become the United States Secretary of Homeland Security, effective March 31, 2026." White House Press Secretary Karoline Leavitt said the administration would work with the Senate to confirm Mullin "as quickly as possible." The Senate must confirm him for the post.

The nomination drew immediate bipartisan reactions. Democratic Sen. John Fetterman of Pennsylvania posted that he is "AYE" on Mullin's confirmation — a notable break from his party. Senate Minority Leader Chuck Schumer called himself "a resounding NO." NPR profiled Mullin as a former UFC fighter and small business owner whose immigration positions closely align with Trump's enforcement-first approach, while CNN noted his confirmation hearings are scheduled this week.

The DHS transition comes as Trump's mass deportation program is scaling up, with billions allocated to hire new ICE officers and build detention facilities toward a stated goal of removing 1 million immigrants this year. NPR and PBS NewsHour both reported that the program is at a crossroads, with Mullin expected to either reset or intensify the current approach.