From what I understand, the Russians had a nuclear ABM battery protecting Moscow which could have destroyed incoming warheads through the brutally simple expedient of taking it out with another nuclear explosion. Obviously, this would have caused its own problems, but it would have been preferable to allowing a direct hit on a major city...
“the Russians had a nuclear ABM battery protecting Moscow “
I think this was called the Galosh system. It was like our Nike-Ajax systems we had here and there. Yes it was nuclear, as was Nike and Ajax. We got rid of ours to comply with some treaty, the treaty allowed Russia to keep galosh in place.
Both systems were more anti-bomber than anti-missile.