Quin and Daniel Larison provide much needed demographic context for this weekend’s special election in Louisiana, explaining why the sixth congressional district is likely to be less Republican post-Katrina than it was when George W. Bush carried it easily in 2004. Michael Jackson (not the singer) may actually deliver the seat to the Republicans in the fall anyway. But I don’t think it’s quite right to say “There hasn’t even been a trend,” at least if Larison is talking about the same trend I’m actually talking about.

If the special elections were all we had to go by, it would be premature to render a judgment. But there is ample evidence that the Republican brand is tarnished — fundraising woes, primary turnout, generic poll numbers, the 2006 elections — and plenty of cases where Democrats have won in areas where Republicans should have been favored. There are good reasons to believe that Democrats will add to their congressional majorities in November. It is against this background that the special elections in Illinois, Louisiana, and Mississippi are daunting for Republicans.

Sure, there are extenuating circumstances in each of the above races. Since politics doesn’t take place in a lab, there are always extenuating circumstances. If it weren’t for scandals, Democrats wouldn’t hold House seats that recently belonged to Tom DeLay, Bob Ney, and Mark Foley. Plenty of extenuating circumstances helped the Republicans pick up formerly safe Democratic seats in 1994. That’s how congressional majorities are built. The stronger party is better than the weaker party at adapting to changing political circumstances, recruiting strong candidates rather than relying on Woody Jenkinses and Jim Oberweises, and seizing opportunities in races that individually would serve as imperfect barometers of the country’s politics.

The only good news for Republicans is that the Democrats are missing two things. In 1994, a large number of conservative congressional districts that had been electing Democrats stopped doing so. The number of Northeastern moderate districts electing Republicans isn’t as large. Second, there hasn’t been a clear public endorsement of the Democratic agenda except where that agenda is small (raising the minimum wage) or more popular in the abstract than in detail (think health care and Iraq).