Rep. Collin Peterson (D-Minn.) will seek reelection this year.

The former House Agriculture Committee chairman's decision to run again is a big break for Democrats. He had publicly wavered about running again, and his retirement would likely have made Republicans the favorites to win his seat.

"There will be a clear choice in this election between Congressman Peterson and his opponent, Sen. Torrey Westrom," Minnesota Democratic party chairman Ken Martin said in a statement. "Congressman Peterson has worked for opportunity for all while Westrom has a record of voting against a fairer tax system, preparing our children for future success and growing Minnesota’s economy.”

Peterson is one of a handful of longtime Democratic incumbents left in conservative-leaning districts. His district voted for Mitt Romney by 10 points in 2012.

Others in similar spots have either retired or face very tough races.

In a statement, National Republican Congressional Committee spokesman Tyler Houlton assured Republicans would still go after the seat.

"As NRCC Chairman Greg Walden likes to say about vulnerable Democrats, 'Either leave on your own terms, or lose in November,'" Houlton said. "Today, it looks like Rep. Collin Peterson decided he’d rather lose in November."