(Bloomberg) -- Kari Lake, an ardent supporter of Donald Trump who refused to concede her defeat in Arizona’s 2022 gubernatorial contest, is running for the US Senate.

Lake, a Republican, filed her candidacy, which had been expected, with the Federal Election Commission on Tuesday. 

The decision could set up a high-stakes three-way 2024 race for the seat held by Senator Kyrsten Sinema, an independent who dropped her affiliation with the Democratic Party last December. The Arizona seat is crucial to the Republicans’ strategy to retake control of the Senate, now governed by Democrats with a 51-49 majority that includes Sinema.

Sinema, who caucuses with Democrats, hasn’t yet said whether she’ll run for reelection. Liberals in the state, who see Sinema as too conservative, are aligning with Representative Ruben Gallego, who already has announced his Senate bid.

Lake’s bid could give Democrats an edge in the Grand Canyon State in 2024, a year in which Republicans otherwise have a remarkably favorable map. Not a single Republican Senate seat on the ballot is currently seen as at risk, while eight seats aligned with Democrats are considered competitive and three of them — in Montana, West Virginia and Ohio — are in heavily Republican states that former Trump won by 8 points or more in 2020.

A former TV news anchor, Lake frequently claimed Trump was robbed of victory in his presidential 2020 reelection campaigned when she sought last year to succeed Arizona Governor Doug Ducey, a Republican. She lost her gubernatorial bid to Democrat Katie Hobbs, 50.3% to 49.6%, but then refused to accept the outcome. The last of Lake’s legal claims in that race was dismissed by an Arizona judge in May.

Lake hasn’t been formally endorsed by the GOP, but polls have shown her ahead in matchups against other declared or possible candidates.

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