Backed by "Tea Party" movement activists and Sarah Palin, Christine O'Donnell delivered another blow to the Republican establishment, winning the party's Senate nomination in Delaware.

O'Donnell's victory gives the GOP a nominee whom Delaware Republican Party Chairman Tom Ross has said can't win in November.

In the primary, Ross backed Mike Castle, a veteran congressman and former Delaware governor who had won 12 statewide races in a row before O'Donnell broke his string on Tuesday.

Republican party leaders saw Castle, a GOP centrist, as their best chance of taking the Senate seat that Vice President Biden occupied for 37 years before joining President Obama's administration.

In the closing weeks of the primary campaign, GOP bigwigs made no pretense of neutrality. Chris Christie, the governor of neighboring New Jersey, campaigned for Castle, while Delaware GOP turned its website into a propaganda machine for him.

The race took a toll on neighborly Delaware, where politicians make a tradition of literally burying a hatchet after Election Day. Castle declared the campaign the most unpleasant of his career. Ross said he received a death threat because of his outspoken opposition to O'Donnell.

Until Tuesday, Castle was viewed as a formidable opponent: After the congressman launched his Senate candidacy, Delaware Attorney General Beau Biden, the vice president's son, announced he would not make the race.

Hours before polls closed Tuesday, O'Donnell said she is ready "to extend an olive branch" to the Republican Party.

Her November opponent is Democrat Chris Coons, the New Castle County executive.

(Posted by Kathy Kiely)