(CNN) - A celebratory Christine O'Donnell thanked her supporters, the Tea Party and kingmaker Sarah Palin on the night of her stunning win in Delaware's Republican Senate primary.
At the same time, party leaders were shaking their heads, watching helplessly as control of the Senate was slipping out of reach.
Republicans were expected to pick up the Senate seat that Vice President Joe Biden held for 26 years with Rep. Mike Castle, a nine-term congressman and popular former governor who appealed to independents and some Democrats, on the ballot.
And in an anti-incumbent year, Republicans had hopes of reclaiming the Senate, where Democrats hold 59 seats, including two independents who caucus with them, and Republicans 41.
But now that it will be O'Donnell facing off against Democrat Chris Coons, Democrats are breathing a little easier.
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