What we saw with Venezuela was something nukes wouldn't prevent. Doing the same with Putin is infinitely harder, but if it did occur, chances are whoever fills in the power vacuum in Russia would be pretty happy with their situation.
I'm not saying chances are with regard to nukes, I'm saying with regard to whoever gets to take over Russia. In either case they definitely aren't using nukes because it means mutual destruction over one man who has 0% chance of ever returning to Russia.
