Former South Dakota Governor Kristi Noem is reportedly weighing a last-minute bid for the U.S. Senate that could pit her against incumbent Republican Mike Rounds in South Dakota’s upcoming primary election.

People familiar with the discussions say sources close to both the White House and the office of John Thune, the Senate majority leader from South Dakota, have been preparing for the possibility that Noem could launch a primary challenge before the state’s candidate filing deadline on March 31st. Noem has not publicly confirmed plans to run, and no formal campaign announcement has been made.

Rounds, who has served in the Senate since 2015, is seeking another term representing South Dakota. The Republican lawmaker previously received the endorsement of Donald Trump for his reelection campaign, a factor that could shape the dynamics of any potential primary contest.

Several privately circulated polls have reportedly been shared among political operatives in recent weeks, suggesting that a race between Noem and Rounds could be competitive if the former governor enters the contest. Details of the surveys have not been released publicly.

Sources close to Noem also indicate that political considerations tied to her departure from DHS may be influencing her thinking. Those sources say she is concerned about possible future scrutiny related to her leadership at the department, including her handling of contracts and her relationship with political adviser Corey Lewandowski. Noem’s tenure at DHS became controversial and drew bipartisan criticism, culminating in her removal by President Trump. There have been no publicly announced investigations involving those matters, and representatives for Noem have not commented on the claims.

Rounds’ office has not publicly addressed the possibility of a primary challenge, and Noem’s political team has not confirmed whether she intends to file to run.

With South Dakota’s filing deadline set for March 31, any decision by Noem to enter the race would likely come soon. Political observers say that if she does move forward, the contest could quickly become one of the most closely watched Republican Senate primaries of the upcoming election cycle.