… Partly because the GOP controlled redistricting in many key states after 2010 and partly because Democratic strength is more geographically consolidated in big cities, the current congressional map gives Republicans a basic structural advantage. … But as we ponder the situation in the House as Republicans appear likely to nominate a potentially polarizing person — Donald Trump or Ted Cruz — to lead their national ticket, we have to consider a world in which the Democrats not only win the White House again, but win it by a bigger margin than Obama did in 2012. As we discussed last week while updating our Senate and gubernatorial ratings, the coattail effect and the higher propensity for straight-ticket voting could prove to be very damaging to the GOP with Trump or Cruz leading the party in 2016. …
To examine the possibilities of a Democratic “wave” in the House, we’ve laid out three basic scenarios based off the 2012 election result as a starting point. These scenarios examine how a one-point, two-point, and three-point increase in Obama’s two-party vote in each congressional district would affect the number of districts won by Obama and Romney. CONT.
Kyle Kondik & Geoffrey Skelley, Sabato’s Crystal Ball