WASHINGTON ? The Senate confirmed Markwayne Mullin as secretary of homeland security on Tuesday, handing President Donald Trump another close ally to lead one of the government's most politically fraught departments.

In its confirmation report, The Associated Press said Mullin won approval in a 54-45 vote as the Department of Homeland Security faced a funding lapse that left TSA officers working without pay and airport delays worsening in several cities.

Mullin's path to confirmation had been contentious. AP's hearing report said Democrats and even some Republicans questioned his temperament and lack of deep immigration-policy experience, while Mullin promised to reverse policies he said had slowed FEMA disaster reimbursements.

The confirmation also immediately reshaped Oklahoma politics. AP later reported that Gov. Kevin Stitt picked Williams Companies chairman Alan Armstrong to fill Mullin's Senate seat until the November election is certified.

Mullin inherits a department where immigration enforcement, airport staffing and disaster response are all under unusual strain, making the confirmation more consequential than a routine Cabinet vote.