The thing is, the Obama worries weren't a result of McCain calling for him to be assassinated or telling his supporters the election was rigged. They were pretty much a direct result of people being scared some crazy racist would take a shot at him.

To be fair, organized voter intimidation by one of the major parties isn't unheard of; Trump is mostly just unique in doing himself what would usually happen deniably at a lower level of the organization (which may or may not be related to the fact that Trump lacks most of the lower-level organization a major party candidate would usually establish.)