Milwaukee County Sheriff David Clarke is passing on a challenge to Democratic Sen. Tammy Baldwin of Wisconsin in 2018, he said in his new book “Cop Under Fire,” according Fox 6 News Milwaukee.

“I have no interest in running for elected office other than being sheriff,” Clarke, who runs as a Democrat, writes in the book.

Two groups had attempted to draft Clarke to run against Baldwin, whose seat is up this cycle and is rated Tilt Democratic by Inside Elections. One of the groups hit Baldwin for her sexuality; she is the first openly LGBT U.S. senator.

Clarke has emerged as a polarizing figure, speaking out against the Black Lives Matter movement. He is a frequent talk show guest and spoke at the Republican National Convention last year.