As annoying as it is that the fool is still alive, I think it would be better for American democracy if he lives and soundly loses the next election, than be a martyr to his rabid followers who would probably have rampaged and broken it fully if he had been killed.
If he fades into obscurity (he'll always have the gong for worst US president ever), then hopefully his influence will fade too. If he were shot at the height of his blustering and rabble-rousing then his name would go down as the patron saint of the republican party.
Of course, if he wins the election that's possibly the worst outcome. Followed by a VERY close loss which causes more uprisings.