Now this is pretty smart. I re-registered to become a Republican to support Trump. I have yet to confirm it went through, but I'm way ahead of the deadline to register. It makes sense to expect voters to make party changes way ahead of the actual election to prevent people such as myself hopping to a party to support a candidate. But if the political parties were really worried about party hopping, then they would get rid of the state run primaries altogether and run the nominations themselves.