Any talk of the US winning WW3 in or after 1968 is delusional. By then, the Soviets had built up the strategic rocket forces to around a thousand ICBMs* and emplaced many of them in hardened silos. The Soviet retaliation to the American first-strike would have effectively eradicated American society as assuredly as the US would have the Soviets.
*To be precise, by the end of 1968 the Soviets had loaded and active launchers for 196 R-16s, 26 R-9s, 163 R-36 vanillas, and 6 R-36-0, and 770 UR-100s. There were also a trio of Yankee-class missile submarines, though those wouldn’t be on regular patrols off the American seaboard until another 11 were added to the fleet in 1968-1970.