At the end of 1965 we had 800 Minuteman I and 54 Titan ICBMs deployed.
The Soviets had 281 ICBMs deployed.
That means we could target 3 of our missiles on each of their missile silos.
The Soviets did not have a ballisitc missile early warning system in 1965, so they would have almost no warning of this first strike.
The Minuteman missile could be launched in less than a minute (which is why it was called the Minuteman).
Soviet ICBMs on the other hand would take over an hour to fuel and get ready for launch.
We also had 384 Polaris SLBMs deployed on 24 SSBNs.
They could be used to take out the Soviet bomber bases.
I am not really saying that we should have attacked the Soviet Union.
I am saying that the Soviet Union would not have attacked us because they would know the consequences of such actions.
It would be the destruction of their industry, agriculture, infrastructure and ten(or hundreds) of millions of their people.