A terrible way to forecast the 2016 contest is to gauge whose supporters are the loudest. Presidential elections are not decided by partisans or ideologues.
The arithmetic is pretty simple: 41% of voters in the 2012 presidential election described themselves as moderates, and 29% as independents. Almost all Republicans (93%) and self-described conservatives (82%) voted for Mitt Romney, but that wasn’t enough. Even if Mr. Romney had won every Republican or conservative voter, it still wouldn’t have been enough.
Because there are roughly 5% more Democrats than Republicans, the GOP needs a solid majority of independents to win a national election. In 2012 Mitt Romney outpolled Barack Obama among independents, 50% to 45%. But that didn’t take him across the electoral college finish line.
It is safe to predict that the proportions that held in 2012 will be about the same this year. About two-thirds of the voters will not be Republicans. Thus it is vital to pay early attention to how each of the candidates is doing among independents. A long, drawn-out primary that forces candidates to make strong appeals to the party’s ideological base can hurt the eventual nominee in November