Rep. Bruce Braley (D-Iowa) will run for the Senate seat held by retiring Sen. Tom Harkin (D-Iowa), he announced in an email to supporters Thursday morning.
Braley has been expected to run for the seat. He recently met with Democratic Senatorial Campaign Committee Chairman Michael Bennet (D-Colo.) and Senate Majority Leader Harry Reid (D-Nev.) to discuss the race, and had been rumored to be interested in a statewide run for years.
Braley promised to "get things done for Iowa's middle class" in the email.
"It's time to start a conversation with Iowans – about rebuilding the middle class, creating economic opportunity for everyone, and keeping America strong," he said.
Braley, a four-term congressman from the eastern part of the state, has proven to be a tough campaigner. He narrowly held on to his slightly Democratic-leaning district during the 2010 GOP wave despite being a top target, and won by a wide margin in 2012 against a strong challenger.
No Republicans have announced bids for the seat yet, though both Reps. Steve King (R-Iowa) and Tom Latham (R-Iowa) are considering running. Polls show that Braley would start off with a big lead over King, a firebrand conservative, while Latham would make it a close race in the swing state.