But in Florida, former state house speaker Marco Rubio's insurgent candidacy drove Gov. Charlie Crist -- who was initially recruited and embraced by the GOP establishment -- from the party. Rubio is now the general election front-runner and has a double-digit lead over Crist, who is running as an independent. Similarly, in Colorado, the latest Rasmussen poll shows primary-winner Ken Buck leading Democratic Sen. Michael Bennet among likely voters by 49 percent to 45 percent.
In Nevada, tea party-backed candidate Sharron Angle was in a dead heat against Senate Democratic Leader Harry Reid, with a CNN/Time poll giving her a slight edge.
GOP party primary winners are leading Democrats elsewhere around the country. In Arkansas, Republican John Boozman holds a 17-point lead over Democratic Sen. Blanche Lincoln. In Kentucky, tea party-backed candidate Rand Paul was said in many news reports to be too conservative to win, but he remains the clear front-runner.
Some recent primary winners triumphed without tea party support. In New Hampshire, former state attorney general Kelly Ayotte, who this week narrowly defeated the more conservative Ovide Lamontagne, was leading Democratic Rep. Paul Hodes. Notably, Sarah Palin, who endorsed O'Donnell, supported Ayotte. Sen. Lisa Murkowski, a Republican, lost her primary to Joe Miller, a West Point graduate who is far more conservative. Polls show that Miller is going to hold this seat in rock-ribbed Republican Alaska.
Clearly, the GOP's primary battles are not hurting their chances to make major gains in the Senate, perhaps six to eight seats.
But Delaware's significance in the general election is that it was seen as a golden opportunity to win a long-held Democratic seat that would give Republicans the best chance to win the 10 needed to topple the Democrats from power.
O'Donnell, a perennial candidate, has run for the Senate twice before, against Biden, and was soundly defeated. Her finances are among her many problems: a near-home foreclosure, a lien by the IRS on back taxes owed, failure to pay student loans and charges that she used previous campaigns to pay her bills. Her recent complaints that people have been hiding in the bushes near her home, spying on her, didn't help either.
Yet she won anyway. Many tea party voters said in post-primary news interviews that in the current recession, they sympathized with her financial difficulties and identified with them.
But Republican strategist Karl Rove called her unelectable, and in a Democratic state like Delaware you have to appeal to more than just your party's conservative base in order to win election.
If Republicans were to pick up nine Senate seats on Nov. 2, just shy of the one seat they could have had just for the asking to take control, all eyes will be on Delaware as the one that got away.