There's literally nothing they can accuse him of, other than the good old "you're a socialist" and "do you want America to become Venezuela" tropes, which will not stand among Bernie's base and most younger people.
Well, the socialist tag will stick, but for his base and many younger people it’s not a pejorative.
And the Venezuela smear is easily countered by asking Trumpists if they really want America to be like Vladimir “Trump’s Buddy” Putin’s Russia.
RE: This Revolution Will Be Televised