Ask HN: How do we stop Trump?

With it looking increasingly likely that Trump will be the Republican nominee, no one should discount the possibility that this insane man could in fact become president.

His extreme anti-immigration proposals would choke off the life blood of America's ability to innovate and his utter hostility to digital rights should raise the hair on the back of the neck of any technologist. Given these issues (not to mention his blatant racism and sexism), everyone in the wider technology community should be concerned with preventing this man from becoming president. What I'm wondering is, what is the best (legal) way for technologically inclined people to oppose and prevent the disaster that would be Trump becoming president?