A must-read: 2016 and Beyond: How Republicans Can Elect a President in the New America by Whit Ayres.
“If the 2016 Republican nominee wins the same percentage of the white vote that Mitt Romney won in 2012 — 59 percent — then he or she will need to win 30 percent of the non-white vote to be elected. That is far greater than the 17 percent of the non-white vote that Romney achieved in 2012, or the 19 percent John McCain won in 2008, and better even than the 26 percent of the non-white vote that George W. Bush won his 2004 reelection campaign.”
“On the other hand, if the 2016 Republican nominee wins no more of the non-white vote than Romney’s 17 percent, he or she will need to win 65 percent of the white vote to win. That is a level of white vote achieved by only one Republican nominee in the past forty years: Ronald Reagan in his 49-state landslide reelection sweep in 1984, when he won 66 percent of the white vote… Republicans can complain about these trends, wring their hands over them, and get heartburn as a result. What they can’t do is change them.”