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WASHINGTON (Reuters) - Democrat Christopher Coons won the Senate race in Delaware on Tuesday, the NBC and CNN TV networks projected, beating out Republican and Tea Party favorite Christine O’Donnell and keeping for Democrats a seat once held by Vice President Joe Biden.

O’Donnell’s loss came after tepid support among Republicans and questions about her background and campaign tactics, which included a widely-criticized television advertisement in which she denied being a witch.

Democrats had worried about losing the seat, particularly in elections where they expect to lose ground in the Senate and House of Representatives. Coons was given active campaign backing by Biden and President Barack Obama.