The fact is that Democrats were on the unfriendly side of two wave elections in the last decade, in 2010 and 2014, while for Republicans, it has been a dozen years since the GOP got hit with one. In 2006, when President George W. Bush’s last Gallup job-approval rating before the midterm election was 38 percent (sound familiar?), Republicans lost both their House and Senate majorities. There is a lot of cherry-picking poll data, searching out the most optimistic numbers around, that seems to be giving some Republicans a degree of complacency that is at odds with averages and hard data.

In an analysis released Sunday of more detailed data from the Jan. 15-18 ABC News/Washington Post poll, much of the national 14-point Democratic lead among likely voters in the generic-ballot question was among voters in districts already represented by Democrats, where they had a 38-point lead—64 to 26 percent. This no doubt was a finding that encouraged Republicans, but the analysis also revealed that in districts already represented by Republicans, the GOP advantage on the generic was just 6 points, 51 to 45 percent. In other words, Republicans have a lot of districts where their leads are very, very narrow while Democrats have very big leads in their districts. It wouldn’t take that much of a wave for a large number of seats to drop against the GOP.