Calls for the most delicate judgment

Today's fun finding is produced by Nate Silver, who finds that Arlen Specter is even more craven than one might have expected: Specter's voting record moves violently around the ideological charts depending on where is challenge-of-the-moment might be. Jason Zengerle and Matt Yglesias both use it to point out the importance for liberals of electoral challenges from the left, even if they don't win, and rightly so. But of course primary challenges, in particular, are a tricky threat. Democrats are to some extent reaping the benefits now of ideologically rigid Republicans; they shouldn't be seeking to set up a mirror Club for Growth that endangers the Nelsons or Baucus by pushing them too far to the left. The question here, I think, is to what extent unleashing primary challenges in sensible places (say, to a moderate Democrat in a liberal state) winds up with the kinds of electoral suicide that the Club is known for. One would think that networked parties (what we have) are at a disadvantage to formally organized hierarchical parties (what other nations often have, and what some US local parties have been in the past) in these sorts of things, since the incentive structures for different nodes within the network may not match the interests of the overall network. It would be nice to know how a strong networked party handles these sorts of questions, what mechanisms they can (do?) use to push each other to put energy into (say) finding a strong general election opponent to Chuck Grassley or a strong primary challenge to Joe Lieberman rather than focusing on endangering a seat by pushing Ben Nelson to the left.