On the Fact that (According to Data Analyst, Steven McIntyre) Computerized Gerrymandering Has Gotten so Sophisticated and Precise that the Vast Majority of Congressional Districts In this Country Are Now Either Dark, Dark Blue or Crimson Red (and, Yes, Both Parties Pull this Shit so Don't Even Attempt to Make it Partisan)

 This could account for why the Republicans didn't perform as well as expected on election day (in addition to some other factors, of course). Just not enough swing districts anymore.