Former Sen. Jim Talent, who has worked as a lobbyist since he was defeated by McCaskill in 2006, is also eyeing the race. Lt. Gov. Peter Kinder is also seen as a possible candidate.
Expect this one to be a top Senate race. Missouri is a perennial swing state, often having close results at the statewide level. On the other hand, it may be starting to trend more to the Republicans, even more than any national swing.
McCaskill defeated Talent by 50%-47% in 2006. Then in 2008, John McCain carried the state by less than one point over Barack Obama -- the first time that Missouri had voted for the loser of a presidential election since Democrat Adlai Stevenson carried it against Dwight Eisenhower in 1956. In the 2010 Senate race, an open seat contest to succeed retiring Republican Sen. Kit Bond, Republican Roy Blunt defeated Democrat Robin Carnahan by the very strong margin of 54%-41%.