Well, the USSR's problem was two-fold: until Cuba they didn't have a place to put their short- and medium-ranged ballistic missiles. They did have ICBMs that c

Well, the USSR's problem was two-fold: until Cuba they didn't have a place to put their short- and medium-ranged ballistic missiles. They did have ICBMs that could hit the US, but 1) there would be enough warning for an immediate counter strike and 2) they just couldn't deliver enough to cripple the US. The Soviet Union's concern was also that the US did have missiles in places like Turkey and Germany, which provided them decent first strike ability that-- until Cuba-- the Soviets didn't have. To my mind, though, the big differentiater was Strategic Air Command. The US had an enormous amount of bombers regularly patrolling outside of Soviet airspace. Had SAC been ordered in there would have been plenty of warning, but it provided massive second strike capability. The Soviet Union had no answer for that and never would, which is why they did opt to go heavy on the ICBMs whereas the US spread out its weaponry across the nuclear triad.