With Trump’s path to 1,237 delegates on such a knife’s edge, every percentage point matters. And it’s possible that Trump has moved a few voters into his column with a series of process arguments that he’s been pressing recently. The more restrained version is that the candidate who gets the most votes should be the Republican nominee — that delegates shouldn’t upend the people’s verdict. In public speeches, Trump has taken the argument a step further, describing the GOP’s nomination process as “rigged” and “crooked.”
http://fivethirtyeight.com/features/trumps-system-is-rigged-argument-is-working/
