Former President Donald J. Trump is expected to endorse Kari Lake for Senate in Arizona as soon as Tuesday evening as she runs in what will be one of the nation’s most consequential Senate races, a person briefed on his thinking said.
Arizona, along with West Virginia, Montana and Ohio, are seen as among the best opportunities for Republicans to pick up Senate seats next year and win back a majority.
The move comes weeks after Mr. Trump told a prospective Republican candidate, Blake Masters, who lost a race for the other Senate seat in the state last year, that he would lose the primary against Ms. Lake if he ran, according to people familiar with their conversation.
Ms. Lake, a Trump ally and former news anchor, embraced the former president’s lies about winning the 2020 election in her failed run for Arizona governor last year. She also refused to accept her defeat. He pointed to her as an example of how to win, in a conversation between Mr. Trump and Mr. Masters that was recorded by a television camera trailing Mr. Masters.
Ms. Lake, who is scheduled to host her first campaign rally on Tuesday, is running for the seat held by Senator Kyrsten Sinema, who dropped her Democratic affiliation last year to be an independent. Ms. Sinema hasn’t announced whether she will run for re-election, but the race already includes Representative Ruben Gallego, a Democrat.
A spokesman for Mr. Trump did not respond to a request for comment on Tuesday evening. A Lake campaign spokesman declined to comment.
Michael C. Bender contributed reporting.
