The U.S. Senate on Monday confirmed Republican Senator Markwayne Mullin of Oklahoma to serve as Secretary of the Department of Homeland Security in a largely party-line vote of 54-45. Mullin replaces Kristi Noem in the role and will oversee the department's immigration enforcement operations under the Trump administration.

The confirmation came with only one Republican, Senator Rand Paul of Kentucky, voting against Mullin, while two Democrats - John Fetterman of Pennsylvania and Martin Heinrich of New Mexico - supported the nomination. Mullin's confirmation occurred during a department shutdown that has left approximately 100,000 of DHS's more than 250,000 employees working without pay, leading to delays and longer lines at airports.

In a separate development, federal judges appointed Robert Frazer, a career prosecutor, to lead New Jersey's U.S. attorney's office, ending months of uncertainty about leadership in the embattled office. The appointment came after a period of upheaval and questions about who was in charge of the federal prosecutor's office in the state.

Mullin, who has maintained relationships across party lines during his time in Congress, represents a return to more traditional Senate confirmation processes. As DHS Secretary, he will serve as one of the primary public faces of the administration's immigration enforcement policies.

The Department of Homeland Security oversees border security, immigration enforcement, and various other security functions. Mullin takes charge of the department at a time when immigration policy remains a central focus of the current administration's agenda.