President-elect Donald Trump will nominate South Dakota Governor Kristi Noem to serve as the next homeland security secretary, two sources familiar with the decision said today, choosing a staunch ally who has little experience on the national security stage.

Noem, once seen as a possible running mate for Republican Trump, is currently serving her second four-year term as South Dakota’s governor after a landslide reelection victory in 2022. She rose to national prominence after refusing to impose a statewide mask mandate during the COVID-19 pandemic.

She will be new to the 260,000-person U.S. Department of Homeland Security and its sprawling mission, which includes border security, countering terrorist threats and cyber security.

Trump focused intensely on border security during his campaign to recapture the White House, sharply criticizing high levels of illegal immigration under Democratic President Joe Biden and Vice President Kamala Harris.

Trump, who won decisively against Harris in last week’s election, has vowed mass deportations and other immigration restrictions beginning on his first day in office.

Noem, whose home state is closer to Canada than Mexico, made several trips in recent years to the U.S.-Mexico border, which she called a “warzone” in January.

As South Dakota governor, she deployed dozens of National Guard troops to assist the Republican-led state of Texas with border security in recent years, including one controversial deployment in 2021 funded by a Republican billionaire. Noem faced widespread backlash in April when she wrote in a memoir that she shot to death an “untrainable” dog that she “hated” on her family farm. Some Trump advisers said they believed Noem’s stock fell in the former president’s eyes after that, at a time when she was still a vice presidential contender.

Both Trump’s campaign and Noem’s office did not immediately respond to requests for comments. Trump on Monday appointed former top immigration enforcement official Tom Homan as his administration’s incoming “border czar.” Stephen Miller, the architect of Trump’s first-term immigration agenda, also is expected to join the new administration as White House deputy chief of staff for policy.

Additional reporting by Ted Hesson.