As I wrote yesterday, with the unemployment rate at 10% and the economy still hemorrhaging jobs, the Democrats are in trouble. Now more than ever they need to field their best slate of candidates. But this week a number of prominent Democrats announced they won't run in the fall, almost certainly in part because they would be facing tough campaigns. As I've argued, Sen. Chris Dodd's (D-CT) decision not to run should actually help the Democrats, since Dodd has been hurt by a number of recent scandals and polls much less well than his likely replacement, Attorney General Richard Blumenthal. But the losses of Sen. Byron Dorgan (D-ND) and Colorado Gov. Bill Ritter hurt much more.
As Andrew Gelman argues in a great post on FiveThirtyEight, this is to be expected. While it is in the interest of the parties to have their most popular incumbents run when the political climate is tough, facing a tough reelection battle may be less appealing to the candidates themselves. As Gelman puts it, "What makes sense for the individual officeholder—stay in when you think you'll have an easy win, and wait to quit when the going is getting tough—isn't so helpful for the national party."
Just as governments might want to practice a countercyclical fiscal policy—spending more when the economy is bad and saving more when the economy is booming—parties would do well to field their most popular incumbents when the climate is tough, but field promising new candidates when the climate is easier. Ideally, the Democrats should have replaced any incumbents who could retire in 2008, when it would have been easier for first-time candidates to win. This would have given young candidates a leg up on this year's election, and would have been like investing in a rainy-day fund. But instead it was the Republicans—unwilling to run races they might easily lose—who retired in droves, contributing to the Democratic landslide.
Just as it always tempting to spend more when you are flush with money, Gelman says, it is tempting for politicians to take advantage of a strong political headwind to win an easy election. Parties face a collective action problem, since what's good for their individual members is not necessarily good for the party as a whole. The fact that potential candidates are attracted by political opportunity likely has the effect of amplifying electoral swings. But parties would be wise to do what they can to smooth out these swings by encouraging long-time incumbents to stop down when party is at its most popular, perhaps by promising them appealing roles as party elders. That said, the economy has made things difficult for incumbents of both parties, with a number of prominent Republicans retiring as well. The big winner this fall may just be the party that manages to convince its old guard to stick around for just one more election.