Rep. Tom Latham (R-Iowa) won't run for reelection, he announced Tuesday evening, opening up a competitive House seat in southwestern Iowa.
"It is never a perfect time or a right time to step aside. But for me, this is the time," he said in an email to supporters. "I want to share with you my decision that I will not be a candidate for any office in November of 2014."
Matheson's seat is seen as a likely pick-up for Republicans, while Democrats think they could win both Wolf's and Latham's seats.
The longtime Iowa congressman is a close friend and ally of Speaker John Boehner (R-Ohio).
His retirement comes as a surprise — just a year ago he'd defeated fellow Rep. Leonard Boswell (D-Iowa) in a hotly contested race, and had turned down national Republicans' pleas to run for an open Senate seat.
President Obama won Latham's district by four percentage points in 2012, but Latham has long outperformed other Republicans in the district.
Democrats have already coalesced around former state Sen. Staci Appel (D) to run against Latham. It's unclear who might run on the GOP side, though some of the Senate candidates in a crowded Republican field are from Latham's part of the state and could choose to drop down to the House race.