The Soviet Union had the ability to destroy every major city in the US. Russia still does.
So does the UK, France, China, India and Pakistan (by now), etc. Are they threats? Sure they are - every last one of them!
So were the Soviets - as are the Russians now. Threats? Sure! But all they have/had is the one "Big Stick". They know that the threat, though awesome, is hollow. Very little is worth the destruction of the entire planet, and the Russians know that as well as we do.
No Nation in the world can best us on the conventional battlefield; especially when we choose the time and place.