MADISON, Wis. (AP) — Republican U.S. Rep. Tom Tiffany said Tuesday that he won’t run for U.S. Senate in 2024 against Wisconsin Democratic U.S. Sen. Tammy Baldwin, leaving an open GOP field with no declared candidates in the swing state a year before the primary.

Tiffany said he will run for reelection representing northern Wisconsin rather than take on Baldwin, who is seeking a third term after an 11-percentage point win in 2018. His decision not to enter the race comes just under two months after fellow Republican U.S. Rep. Mike Gallagher also declined to run.

Tiffany, who has been in Congress since winning a special election in May 2020, announced his decision in a statement to the Northwoods River News.

“While Tammy Baldwin is vulnerable due to her record as a rubber stamp for President Biden, I can make the greatest impact continuing to serve the great people of Wisconsin in the House of Representatives,” the newspaper quoted Tiffany as saying.

Tiffany did not immediately respond to messages seeking comment.

Baldwin is viewed as a formidable opponent due to her strong showing six years ago, her high profile across the state and her ability to raise money.

Democrats, including Baldwin, are defending 23 seats in the U.S. Senate in 2024, including two held by independents who caucus with Democrats. That’s compared with just 10 seats that Republicans hope to keep in their column.

Wisconsin’s other senator, Republican Ron Johnson, narrowly won reelection to a third term in November. Baldwin will be on the ballot in a presidential year in a state where four of the past six presidential elections have been decided by less than a percentage point.

Other Republicans considering a Senate run are Madison businessman Eric Hovde, who lost in a Republican primary for Senate in 2012, Franklin businessman Scott Mayer and former Milwaukee County Sheriff David Clarke, a staunch supporter of former President Donald Trump who backed false claims of fraud after the 2020 election.

Tiffany’s decision not to run “leaves Republicans staring down a messy and chaotic Senate primary with two self-funding millionaires and Sheriff David Clarke ready to enter the race,” said Democratic Party spokesperson Arik Wolk.