At some point, party leaders could pull together key contenders and make deals to get selected competitors to drop out and perhaps even endorse a non-Trump alternative. The idea would be to keep Trump from winning primaries with pluralities. Of course, the strategy could backfire. If The Donald has a majority of delegates, he'll be the nominee. Then, it would be 1964 all over again, as already noted in this thread.
Interesting reading:
http://fivethirtyeight.com/datalab/donald-trump-wont-win-a-war-against-fox-news/
