Trump Replaces Homeland Security Secretary Noem with Senator Markwayne Mullin

US President Donald Trump announced the firing of Homeland Security Secretary Kristi Noem, appointing Oklahoma Senator Markwayne Mullin as her replacement effective March 31, 2026. Noem will become Special Envoy for the new "Shield of the Americas" security initiative focused on the Western Hemisphere. Noem faced bipartisan criticism over immigration enforcement tactics, a $220 million ad campaign, and handling of protests after two Minneapolis shootings. Mullin, a Trump ally and former MMA fighter, supports strict border policies and will require Senate confirmation.