Nolan McCarty writes:

Saxby Chambliss won reelection in the Georgia Senate run-off by a somewhat surprising margin 57-43% margin over Democrat Jim Martin. . . . there seems to be an emerging pattern of the newly elected president’s party losing in run-off elections. Of course, the closest parallel was in Georgia in 1992 when republican Paul Coverdell beat incumbent Democrat Wyche Fowler following Bill Clinton’s presidential victory. . . . Political scientists and economists such as Alberto Alesina, Howard Rosenthal, and Mo Fiorina have offered a “balancing” explanation as to why the new president’s party performs poorly in these special elections and in midterm elections generally. The basic idea is that most voters are more ideological moderate than the two parties and therefore would like to balance them through divided government. . . . in a special or midterm election, voters have a clear opportunity to promote balance by voting against the president’s party.

Isn’t there a simpler explanation? Runoff elections generally have lower turnout than general elections (especially if the general election has the president on the ballot). Lower-turnout elections generally favor Republicans and conservatives. Chambliss won a plurality in the primary election, then you go to a lower-turnout runoff and you’d expect him to do even better, which he did. (Similarly for Republican candidate Coverdell in 1992.)

Is “balancing” really needed to explain this at all?

P.S. I agree with McCarty that the whole 60 votes thing has been overemphasized. Realistically there’s a limit to how many times the minority will want to filibuster against legislation that is popular enough to be passed by a majority in the House and Senate.