Sen. Mike Braun, R-Ind., has formed a campaign to run for governor in 2024, according to paperwork filed Tuesday.
The development, first reported by Politico, had been expected for months, with Braun hinting hard that he was interested in the race.
Josh Kelley, Braun's chief of staff and senior political adviser, acknowledged the filing and said Braun, a first-term senator, "will be making an official announcement of his candidacy very soon."
Braun's decision opens up a Senate seat in what has become a reliably red state since he unseated Democratic Sen. Joe Donnelly in 2018. The state's other senator, Republican Todd Young, was re-elected by a convincing margin this month.
Republican Gov. Eric Holcomb is term-limited in 2024, and Braun is likely to face competition for the GOP nomination to succeed him.
Eric Doden, the former head of the Indiana Economic Development Corp., has been running since early 2021. On his campaign website, Doden emphasizes his appointment by then-Gov. Mike Pence, who later was elected vice president under Donald Trump and is believed to be considering a presidential bid in 2024.
Other possible GOP contenders include Lt. Gov. Suzanne Crouch and retiring U.S. Rep. Trey Hollingsworth.
Braun bested Luke Messer and Todd Rokita, who at the time were House members, in a competitive Republican primary in 2018.
In a statement Wednesday morning, Indiana Democratic Party Chair Mike Schmuhl greeted Braun's candidacy with derision.
"As a so-called businessman, Mike Braun has done very little to improve Indiana as a U.S. senator and he surely won’t do it as governor," Schmuhl said. "Braun’s half-hearted efforts have been ineffective, and he’s been more likely to be spotted on national cable TV shows than talking to Hoosiers in real life about solving real problems."