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.
Rep. Elijah Cummings, D-Md., right, hugs Harold Schaitberger, General President of the International Association of Fire Fighters, after the Congressman spoke at the IAFF's Legislative Conference General Session at the Hyatt Regency on Capitol Hill, March 9, 2015. The day featured addresses by members of Congress and Vice President Joe Biden.