The Jupiter C and Vanguard rockets were inferior to the R7. But that doesn't translate into military inferiority (Eisenhower knew this, but the public didn't buy it).
The Americans didn't need the same capacity as the Soviets in rockets for several reasons. First, US nuclear weapons were supposedly half the size of the Soviets'. Second, the Americans had air superiority. Third, the Americans had land next to the Soviet Union (thus didn't need to fire as far). Fourth, the R7 that launched Sputnik took hours to load. And could not be on standby indefinitely.
Both space programs were stunts in the early days. But using a Saturn V to deploy nuclear warheads is like using a flame thrower to start a barbecue. It could have been done, but there are easier/cheaper ways.
The Americans didn't need the same capacity as the Soviets in rockets for several reasons. First, US nuclear weapons were supposedly half the size of the Soviets'. Second, the Americans had air superiority. Third, the Americans had land next to the Soviet Union (thus didn't need to fire as far). Fourth, the R7 that launched Sputnik took hours to load. And could not be on standby indefinitely.
Both space programs were stunts in the early days. But using a Saturn V to deploy nuclear warheads is like using a flame thrower to start a barbecue. It could have been done, but there are easier/cheaper ways.