Former Wisconsin Sen. Russ Feingold, a Democrat, will run in 2016 for the seat he lost to Republican Sen. Ron Johnson.
He made the announcement via a video on his website.
Feingold served three terms, starting in 1993, before Johnson ousted him in a midterm election in 2010 by five percentage points. Most recently, the 62-year-old Feingold has been teaching at Stanford.
Johnson has said he plans to seek a second term. His supporters released a statement Thursday, reading in part "Wisconsin families rejected Feingold's broken promises and his liberal record once and they are going to do it again."
If indeed a rematch takes shape, it may be a priority for Democrats as they try to regain control of the U.S. Senate. No other Democrat has yet expressed an interest in running.
