Barack Obama used the rules to steal the election from Hillary. The GOP has used the rules to get their unpopular candidate the nomination. Now, Hillary and the GOP are using the rules to make sure their candidates run against each other, not the candidates that people want.
The truth is, these political parties are private clubs, not part of the government. How they select their candidates is totally up to them, not the voters. They set up rules designed to help establishment candidates gain an advantage over outsiders.
What if Trump and Bernie Sanders just decide to go 3rd party and run on an independent ticket. I know they have different ideologies, but I think the establishment needs to be aced out of the equation because of the way they're running this country into the ground. I don't think most of America can handle another 4 years of the Keynesian Economics and we can't handle the destruction of our health care system. We can't handle 4 more years of Congress ripping off our futures by stealing from the Social Security fund. We can't handle $25 trillion in debt. But if we let them pick our candidates for us again, that's what we'll get.