Wait until the convention. Once Trump is officially declared the nominee, the rest will come on board.
As Convention then Election comes all this will be called the pause before the storm. I feel the storm will be fast and furious, but more it will last. Once you give a voter the ability to say my vote counted more will charge forward. The Day has come, be patient and remember we have been in a blitz of Daily jabs of nominee’s .Now wait for the final stanza.