Basically, the Soviets squeezed all they could out of them and didn't need them any more. They were very, very helpful—much more than the USSR liked to acknowl

Basically, the Soviets squeezed all they could out of them and didn't need them any more. They were very, very helpful—much more than the USSR liked to acknowledge—to the early Soviet rocket program, but even with their help, Russia had something like only four ICBMs capable of reaching the US during the "Missile Gap" that JFK in part won the presidency in 1960 over.