Not only rigged, but we see the GOPe folks trying to fine tune the rigging to ensure the will of the people is smashed....
We need to use the momentum, that is against the establishment, if Trump loses, to start a new party. Trump can lead it and we can disrupt the system for a long time. With this election the US system has been changed forever. The Jeannie cannot be put back into the bottle. Who is the next Trump ? Who will be , more radical ? Because the people will be with that person.
They're not very good at it, though. Note that the GOPe choice for U.S. Senate in Colorado got waxed by the insurgent candidate -- Darryl Glenn -- by a 70/30 count.
The real problem the Trump campaign has with caucus and convention states is that either they a.) don't know how to compete or b.) choose not to compete and, in any case, c.) prefer to whine about it.