The U.S. Senate has confirmed Markwayne Mullin as Secretary of the Department of Homeland Security, replacing Kristi Noem, as the agency continues to grapple with an ongoing shutdown.

Mullin’s nomination was approved in a 54–45 vote on Monday, drawing support from both Republicans and Democrats. Senator Rand Paul was the only Republican to oppose the confirmation, while Democratic senators John Fetterman and Martin Heinrich voted in favour.

President Donald Trump had earlier endorsed Mullin, describing him as well-suited for the role and expressing confidence in his leadership.

The confirmation process was marked by a tense exchange between Mullin and Senator Paul during a hearing, where past remarks made by Mullin were brought into question.

Despite the confrontation, Mullin secured enough bipartisan backing, with Fetterman citing a working relationship with the nominee and expressing belief that his leadership would mark an improvement.

Mullin takes over the department at a time of operational strain, as the shutdown has disrupted services, including extended wait times at airports due to staffing shortages. The administration has authorised immigration enforcement officers to assist airport security personnel in response.

In his remarks during the confirmation process, Mullin said his priority would be to stabilise the department’s operations and improve public confidence in its activities.

Lawmakers, particularly Democrats, have continued to push for changes to immigration enforcement policies following recent controversies tied to protest-related deaths.

Mullin, a former mixed martial arts fighter and long-serving lawmaker from Oklahoma, is regarded as a strong supporter of the administration’s immigration agenda and has built relationships across party lines in Congress.