Democrats end this election cycle moving up from 53 to 55 Senate seats -- an especially impressive achievement when one considers that they were defending many more seats than Republicans. That they still have control of the chamber is a gift from the Republican base, which thrown away three or four good Senate candidates in each of the last two elections. Consider:
The problem Senate Republicans keep having is that extremists defeat their more electable candidates in primaries. Jonathan Bernstein writes that "in Senate races, Democrats appear to have had a massive advantage in recruitment" which I suppose could be true at some level. But the really serious problem shows up at the point where the best candidates you've recruited have to win a primary. They get defeated by extreme conservatives who in a surprising number of cases have callous attitudes towards rape victims.
- 2010, Colorado - Republicans nominate Ken Buck, who as District Attorney refused to prosecute a rapist who had confessed to police and to the victim. Buck claimed that the victim was just suffering from "buyers' remorse." They reject the more moderate and accomplished Jane Norton, a former Lieutenant Governor [edited, I had the wrong Norton before]. Michael Bennet defeats Buck by a tiny margin and retains the seat to which he was appointed.
- 2010, Connecticut - Linda McMahon decides to spend some of her vast wrestling fortune on the Republican Senate nomination. She gets it instead of respected moderate former Congressman Rob Simmons. Richard Blumenthal crushes her in the general election.
- 2010, Delaware - Republicans nominate anti-masturbation crusader and self-described non-witch Christine O'Donnell instead of electable moderate Mike Castle. Chris Coons, who was expected to lose against Castle, wins easily against O'Donnell instead.
- 2010, Nevada - With Harry Reid slamming Sue Lowden for her suggestion that health care could be paid for by the frontier-era method of chicken barter, Republicans pick the even more crazy Sharron Angle instead of Lowden or Danny Tarkanian. Angle is literally not ready for prime time -- her staff severely limit her contacts with the media so that she doesn't blow up her own campaign by being crazy on TV. Nevertheless, Harry Reid wins re-election by a solid 6% margin despite 14% unemployment in the state.
- 2012, Connecticut - Linda McMahon decides to spend more of her vast wrestling fortune on the Republican Senate nomination. She gets it instead of respected moderate former Congressman Chris Shays. Chris Murphy crushes her in the general election.
- 2012, Indiana - With strong Tea Party backing, Richard Mourdock unseats the distinguished Richard Lugar, who would've cruised to re-election. Mourdock is a slight favorite for re-election until a debate in which he claims that pregnancies from rape are part of God's plan. With strong support from women voters, Mourdock is defeated and Joe Donnelly is elected instead.
- 2012, Missouri - Facing likely defeat at the hands of Sarah Steelman or John Brunner, Claire McCaskill runs an ad criticizing Todd Akin during the primary as the "true conservative" who might be "too conservative" for Missouri. The reverse psychology works on Republican voters, who nominate Akin. Akin infamously implies that women claiming to have gotten pregnant through rape actually wanted it to happen, because in a "legitimate rape" female biology can shut down the pregnancy. Voters recoil in horror and elect McCaskill by a substantial margin.