Sen. Markwayne Mullin (R-Okla.) speaks to reporters on Capitol Hill in Washington, Feb. 11, 2026. President Donald Trump fired Homeland Security Secretary Kristi Noem on Thursday, March 5, and announced plans to replace her with Sen. Mullin. (Eric Lee/The New York Times) By MAGGIE HABERMAN, HAMED ALEAZIZ, MICHAEL C. BENDER and MICHAEL GOLD  President Donald Trump fired his embattled homeland security secretary, Kristi Noem, on Thursday and announced plans to replace her with Sen. Markwayne...