So, if I say "someone could point a gun at someone and fire," I'm guilty of murder?
The mere mention of a crime isn't committing that crime itself. There's nothing it what Yankee said that would indicate that his statement is a threat. I'd go as far as to say it's a warning that it might cause rebellion--as in, an anti-rebellion statement. No matter what, there is no way whatsoever to call Yankee's statement illegal. The only potential breach of the law here is the Attorney General's waste of forum space while there's a communist revolution in the Midwest.
At least, that's my mostly unqualified and completely unsolicited opinion on this witch hunt.
Fixed