The Senate on Saturday voted for Kristi Noem to become President Trump’s Homeland Security secretary, giving him a loyal lieutenant at the helm of the department that will carry out his border and immigration plans.

Ms. Noem was confirmed on a 59-34 vote, with Republicans expressing confidence in her abilities and her Democratic opponents chiefly registering their disapproval of Mr. Trump’s agenda rather than of her.

Also Saturday, she resigned as South Dakota governor, with Lt. Gov. Larry Rhoden filling the state’s top spot.

Ms. Noem delivered a strong performance in her confirmation hearing this month, declaring the border situation an “invasion” and a “war zone.”

She also sounded the right notes for GOP senators who said Homeland Security has been adrift in recent years, pulled from its core missions and earning self-imposed black eyes from the Biden administration’s Disinformation Governance Board, the near-death assassination attempt on Mr. Trump last summer and mishandling of questions surrounding the New Jersey drone sightings.

“My mission is to build trust,” Ms. Noem told senators.

It will be a major transition for Ms. Noem, who runs a state government with about 13,000 employees. Her new department is 20 times that size.

Its agencies span everything from border enforcement and airport screening to customs duties, emergency management and handing out U.S. citizenship. The department also oversees the Secret Service, the Coast Guard and federal cybersecurity.

It has always been a bit of a Frankenstein’s monster, created in the wake of the 2001 terrorist attacks and tasked with preventing a repeat. On that score, it’s been largely successful, but it has struggled with other missions, including presidential protection at the Secret Service and delivering emergency relief through the Federal Emergency Management Agency.

Still, most of the focus on Ms. Noem will be on how she handles immigration, which was one of Mr. Trump’s top issues in last year’s campaign and, his aides argue, a major reason he won.

Democrats who voted against her said they feared Ms. Noem would be too focused on immigration to the exclusion of the department’s other roles. They also said they don’t think she will defy Mr. Trump.

“It’s become clear to me that she is not fit for the job,” said Sen. Alex Padilla, California Democrat.

• Stephen Dinan can be reached at sdinan@washingtontimes.com.