Trump taps Sen. Markwayne Mullin after firing Kristi Noem as DHS secretary | 5 March 2026 | President Donald Trump on Thursday said he was ousting Homeland Security Secretary Kristi Noem from that post and replacing her with Sen. Markwayne Mullin, an Oklahoma Republican. Noem’s chief advisor, Corey Lewandowski, will also leave his position at the Department of Homeland Security, MS Now reported. Trump’s termination of Noem, MS Now reported, was largely due to her claim in testimony to a Senate panel on Tuesday that the president had personally approved a $220 million taxpayer-funded ad campaign about DHS immigration enforcement. The campaign, which involved a Republican consulting firm with ties to Noem and DHS, prominently featured Noem in commercials.