KS-4 Special Election Means Something or It Doesn't

Last night there was a special election in KS-4 a red district centered in Wichita. Republican Rob Estes won 53%-45%, a lackluster performance considering that Mike Pompeo won 61%-30% a few months ago.

Why It Means Something
The most obvious answer is that if Republicans are winning districts they won by 31 points by only 8 in 2018 they are going to lose a lot of seats. In 2008 and 2010 there were a number of special elections where the Democrats, in the former, and Republicans, in the latter, overperformed what they normally would do. These were signs that a wave was coming.

Why It Means Nothing
There were also elections in those cycles that swung the other way, where Republicans overperformed in 2008 and Democrats overperformed in 2010. This falsely led the parties to think there might not be a wave. On the other hand there were special elections in the 2004 and 2012 cycles where Democrats overperformed. These weren't indicative of a wave. It should be noted that the Kansas environment is positive for Democrats. Governor Sam Brownback is unpopular and Rob Estes is the state treasurer. That won't be the case in GA-6 or MT-AL, so those races might show if this close race was due more to Kansas or the national environment.

When will we know whether this election meant something? Possibly not until after the 2018 election. And that's not helpful at all.