Oh, I don't mean to say that the Russians pretend not to have actual missiles, but that they have some which are specifically set aside to defend Earth from asteroids.
The "how stupid do you think we are" quote refers to what Washington's reaction to such a claim would be. Remember, at this point in time it was thought that pretty much all the large asteroids were in a stable orbit and that Earth wasn't in any real danger. Sure, the occasional football stadium sized rock would come at us but nothing too serious. Asteroid's wiping out the dinosaurs? Not even theorized yet.
Such an announcement would be seen by the West as a laughable waste of money and resources at best, if not an insult to Western intellegence.
I know that. The design was capable of 100 MT at 27 tons, though, so scaling and putting 200 MT on a missile that can lift 95 MT shouldn't be hard...you might even be able to throw a couple of decoys in.
Doubling the amount of material does not make a nuclear weapon twice as powerful.