Iowa Rep. Bruce Braley says he will run for the U.S. Senate seat being vacated by Democratic Sen. Tom Harkin.
Braley said Thursday in an email to potential supporters that the decision is "a big responsibility" and he's forming a fundraising committee to get started.
The Waterloo Democrat was elected to the House in 2006.
He has been eyeing a Senate run since 2010 and his announcement follows Harkin's Jan. 26 announcement that he will not seek a sixth term.
Braley had already said he was weighing a run, and he met last week in Washington with Senate Majority Leader Harry Reid and chairmen of the Democratic Senatorial Campaign Committee.
Among Republicans, Iowa Reps. Tom Latham and Steve King are considering Senate campaigns.