There is no way two nuclear superpowers going to a war. It would be a collective suicide. Even if they didn't use nuclear weapons it still be an economic suicide without a clear winner. Evenmore in 1950s when China was in the lowest point of their 4000year history they could still push US for a stalemate in the Korean war. No way US can beat China now militarily.
And ofcourse in the current era cyber warfare will replace traditional war-fare if ever 2 superpowers decide to wage war .I am pretty sure both countries have planted enough bugs in each other's networks to use if necessary.