U.S. Rep. Sean Duffy is planning to leave his northern Wisconsin congressional seat next month, the Wausau Republican announced Monday. 

Duffy is stepping down Sept. 23 ahead of the birth of his ninth child, who is due in late October and has a heart condition, he wrote in a Monday Facebook post.

"With much prayer, I have decided that this is the right time for me to take a break from public service in order to be the support my wife, baby and family need right now," he wrote. 

Duffy, 47, has been considered a potential U.S. Senate or gubernatorial candidate in 2022. He has held the 7th Congressional District seat since he was first elected in 2010. Last fall, he won re-election to his fifth term, carrying the sprawling district by more than 20 percentage points.

Wisconsin Republican Party Chair Andrew Hitt praised Duffy as "an exceptional proponent of our conservative ideals."

"We are extremely grateful for his years of service and friendship," he said in a statement. 

Duffy's term is set to expire in 2021. A spokeswoman for Gov. Tony Evers said the governor will call a special election to fill the vacancy, and his office is still looking into those requirements.

GOP state Sen. Tom Tiffany, who lives in the 7th Congressional District, said in a statement he's "been receiving a number of calls asking about what’s next."

"I plan to talk to my wife Chris and my daughters, and my future plans will be announced soon," the Minocqua Republican said. 

On the Democratic side, state Rep. Nick Milroy, of South Range, wrote in an email that he's considering a bid "and will be making a decision in the next couple of weeks."

Other potential candidates include state Sen. Janet Bewley, of Mason, and Margaret Engebretson, who ran for the seat last year as a first-time candidate but lost to Duffy. 

The Cook Political Report's 2020 House rankings rate the seat as "solid Republican," with a plus-8 GOP advantage. 

In 2010, during a nationwide Republican wave, Duffy succeeded former U.S. Rep. Dave Obey, a Democrat who represented the district since 1969, becoming the state's longest tenured member of Congress in history.

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