If Russia launches enough nukes to make sure America (and the UK and France) can't respond in kind (which it can't anyway as they all have subs at sea with nuclear strike capability), then the whole planet is rooted and human civilisation no longer exists, so it's kind of a moot point.
100 nukes is easily enough to destroy the world, so anything more than this is superfluous - or do you think there is a scenario in which Russia may be able to launch all 6,000 of its nukes?
There is no rational or logical scenario in which Russia can successfully use its nukes, they would only be used if he has gone completely insane. And if that's the case he should be taken out for the sake of life on earth.
