Any attempt will come from the left or extreme left to provoke that happening. No person in their right mind would even consider doing that. Think of the '68 Dem convention riots, combined with the Watts and Rodney King verdict riots, going nationwide. Just for fun, let's toss in any Detroit Team winning a championship.
Doubt anyone will argue with that, which is why no one will ever go after Obama directly.
Having said that, if the only options for freedom and liberty are a cleansing of the gene pool, it wouldn't be the first time that option was used.