O’Donnell defeats Castle in Delaware

In one of the biggest upsets of the 2010 elections so far, tea party favorite Christine O'Donnell has defeated longtime GOP Rep. Mike Castle in Delaware's GOP Senate primary.

O'Donnell, relatively unknown until the last two weeks, easily defeated Castle, a moderate who had been heavily favored to win the seat in November. The upset is a major disappointment for the national GOP, who had believed a Castle win in November might help the Republicans reclaim control of the Senate.

But many Republicans are openly skeptical that O'Donnell can win the general election in November against Democrat Chris Coons. Texas Sen. John Cornyn, chairman of the National Republican Senatorial Campaign Committee, told CNN he has "doubts" that O'Donnell can win and has declined to say whether the party will spend money in the race.

(Photo by Rob Carr/AP)