Shays will likely face an uphill battle against former Worldwide Wrestling Entertainment CEO Linda McMahon in the Republican primary. McMahon spent $50 million of her own money on her 2010 Senate bid, but lost to now-Sen. Richard Blumenthal (D-Conn.).
Rep. Christopher Murphy, former Secretary of State Susan Bysiewicz and state Rep. William Tong are running for the Democratic nod.
Sen Mary Landrieu, D-La., poses for a selfie with LSU football fans as she campaigns at tailgate parties on the Louisiana State University campus before the LSU-Mississippi State game on Saturday, Sept. 20, 2014. Buy photo here.