House 2016: How a Democratic wave could happen

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. A Democratic improvement by three points nationally would reach the 55% two-party upper limit discussed above. To be sure, in 2016 there will not be a perfectly consistent change in vote support from the 2012 baseline for either party throughout the country. And there is also the possibility of a significant third-party or independent candidate emerging who could scramble this math — for now, these calculations assume that one does not, but that is far from certain.

Nonetheless, a national swing across all congressional districts demonstrates the potential effects of the GOP nominating an outside-the-mainstream standard-bearer. Table 1 lays out the outcomes when one moves Obama’s 2012 two-party vote up one, two, and three notches.