Markwayne Mullin faces Senate scrutiny over his conduct and policies during his confirmation hearing for Homeland Security Secretary on March 18, 2026.

Markwayne Mullin, President Trump’s nominee for Secretary of Homeland Security, appeared before the Senate for his confirmation hearing on March 18, 2026, facing questions about his temperament and past conduct, including a 2023 Senate incident involving Teamsters leader Sean O’Brien, who sat behind Mullin without incident. Mullin emphasized the need for increased funding for the department and defended his qualifications, while senators questioned his record on immigration and border security.