This seat, formerly held by Vice President Biden had seemed like an easy pickup opportunity for Republicans earlier in the cycle. The GOP had recruited Congressman Mike Castle, who had never lost in an election in more than 40 years of Delaware politics, and he easily led in all the polls. But then the Tea Party rebellion against moderate Republicans overtook Castle, as support built up for O'Donnell and propelled her to an upset victory in the primary.
At that point, it became clear that Democrats were probably going to hold the seat.
O'Donnell faced a variety of questions during the campaign surrounding her past statements as a TV pundit, on such issues as her 1990s anti-masturbation activism, her past dabbling in witchcraft, her dire warnings about genetically-engineered lab mice with human brains and other extreme statements.
O'Donnell also had other problems, such as an inability to name any recent Supreme Court decisions with which she disagreed, and questions about her personal and campaign finances.
But chances are, we probably haven't seen the last of Christine O'Donnell. This was in fact her third campaign for Senate, following unsuccessful bids in 2006 and 2008. With the stardom she attained this year, she could easily have the clout with conservative activists to mount another campaign in the future -- or perhaps just get a nice paying job as a commentator on Fox News.
Late Update: Watch Coons' and O'Donnell's speeches.