Stacy Garrity, Pennsylvania's two-term elected state treasurer, said Monday that she will seek the Republican nomination to challenge Democratic Gov. Josh Shapiro's reelection bid, setting up what could be a contest between a low-profile officeholder and a potential White House contender in 2028.

The Pennsylvania Republican Party plans to endorse a candidate for governor in September — nearly half a year earlier than in the past — in an attempt to learn from its 2022 losses and capitalize on its 2024 successes.

Republicans hope Ms. Garrity, the state treasurer, will give them a shot against Gov. Josh Shapiro. But he will be tough to beat, and the Republican field could still be complicated by Doug Mastriano.