Republican senators celebrated President Trump's decision to replace Homeland Security Secretary Kristi Noem with Sen. Markwayne Mullin (R-Okla.).Why it matters: Congressional Republicans — along with the White House — are eager to turn the page on a department that's dragging down the party's image on immigration, the very issue it rode to victory in 2024.Trump wasn't a "happy cowboy" about Noem and her $200 million media campaign, Sen John Kennedy (R-La.) said. Many Senate Republicans were jus...