Hagerty touted Trump's endorsement in numerous political ads and even dressed his team in "Endorsed by Trump" apparel at rallies.
"Looking back in history, unfortunately, Hitler was right about what was taking place in Germany. And who was behind it," Steve West said on a radio show in 2017.
"We knew he was going to get impeached and he deserved to be impeached."
Former vice presidential candidate endorses Wisconsin congressman's primary challenger, Paul Nehlen.
Trump's resounding New York primary victory puts him on the fast track to the Republican nomination.
Voters enrolled in a small right-wing party thinking they were registering as independents.
He's in third place and that's unlikely to change.
David Cameron called Trump's plans "divisive, stupid, and wrong"