Gavin Newsom (D) says his heart is in California, not D.C.
Centrist Missouri Democrat says she can have biggest impact by remaining in the Senate.
Antonio Villaraigosa said he is “seriously” considering running for the open seat.
The environmentalist is moving towards bid to replace one of Senate’s green champions.
The West Virginia Democrat is considering running for the job he held from 2005 to 2010.
Sen. Barbara Boxer’s (D-Calif.) retirement is setting off a chaotic scramble to replace her.
Ex-Secretary of State Condoleezza Rice has no interest in the Senate, an aide says.
Sources close to the GOP congressman say he won't join race to succeed retiring Boxer.
The House minority leader called her close friend's decision a "great loss" for the country.
The California Democratic senator's exit will attract a large crowd to succeed her.