I don't think that was true, though it could have been possible at the very beginning when the Cheyenne Mountain complex was being built in 1960. But I'm skeptical for a few reasons.
One is the infamous "missile gap," which Kennedy arguably used to help win the 1960 election. This was a belief that the Soviets had many more warheads and missiles than us, and was completely untrue. If this was the belief (at least as of 1959/1960), then it doesn't make too much sense to design an expensive "missile sponge" such as this.
With the introduction of long range bombers, sub launched missiles and land based ICBM's, each side had so many nukes by the 60's, that the Soviets could have dropped a hundred nukes on the mountain and they would still have enough warheads to drop on every decently sized American city. (in 1965, they had over 6000 warheads, by 1970 they had over 11,000 [1], it grew from there.) It's also worth noting that nuclear warheads/missiles both became much more powerful and more accurate during this time.
Another thing that makes me question this, is the book Command and Control that I mentioned earlier in the comments. From reading it, the author's thesis is that there was no true command and control up until the 1980's (and even then...) That's to say, it existed, but it had many problems such as difficulty of communications between each missile site/air base/sub, slow speed in communications, various organizations that were involved, lack of adaptability, and then have all of this happen while the country is being nuked. (Many of the things that modern telecommunications were designed specifically for, and have arguably solved, less the very important human element.) All of this is to say, a centralized place and system for a control hub was very necessary to both determine if an attack was occurring and how to respond to said attack.
I don't think it would have been a very effective warhead sink.
btw, with the Missile Gap, also check out the Bomber Gap. Yay American Military Industrial Complex, nothing like using a little bit of fear to make some money building unnecessary weapons of war and getting politicians elected to office! It's a win win!
It's not a claim that can be easily substantiated, but the USSR did have special ICBMs with single high yield warheads instead of MIRVs earmarked for that kind of target.
One is the infamous "missile gap," which Kennedy arguably used to help win the 1960 election. This was a belief that the Soviets had many more warheads and missiles than us, and was completely untrue. If this was the belief (at least as of 1959/1960), then it doesn't make too much sense to design an expensive "missile sponge" such as this.
With the introduction of long range bombers, sub launched missiles and land based ICBM's, each side had so many nukes by the 60's, that the Soviets could have dropped a hundred nukes on the mountain and they would still have enough warheads to drop on every decently sized American city. (in 1965, they had over 6000 warheads, by 1970 they had over 11,000 [1], it grew from there.) It's also worth noting that nuclear warheads/missiles both became much more powerful and more accurate during this time.
Another thing that makes me question this, is the book Command and Control that I mentioned earlier in the comments. From reading it, the author's thesis is that there was no true command and control up until the 1980's (and even then...) That's to say, it existed, but it had many problems such as difficulty of communications between each missile site/air base/sub, slow speed in communications, various organizations that were involved, lack of adaptability, and then have all of this happen while the country is being nuked. (Many of the things that modern telecommunications were designed specifically for, and have arguably solved, less the very important human element.) All of this is to say, a centralized place and system for a control hub was very necessary to both determine if an attack was occurring and how to respond to said attack.
I don't think it would have been a very effective warhead sink.
[1] https://en.wikipedia.org/wiki/Historical_nuclear_weapons_sto...
btw, with the Missile Gap, also check out the Bomber Gap. Yay American Military Industrial Complex, nothing like using a little bit of fear to make some money building unnecessary weapons of war and getting politicians elected to office! It's a win win!