So how do we sanction him? He's not the head of state. He's the Crown Prince. He has a lot of real power, but we're not the ones who granted him that power, and we can't take it away.
I don't think he's visited the States in some time, so I don't know what we could do here. Unless he owns property.
Maybe we're jumping the gun here. Why take public actions that could undermine MBS? Can't we make life more difficult for him financially, cyber wise, otherwise?