The United States won World War 1 and 2 primarily because the USA was a manufacturing powerhouse. Sadly, that is no longer true. The mighty steelworks and factories that provided the material support for the allied armies are rusted ghosts of their former glory, not easy to resurrect. For that reason and the current economic reality that no nation will loan the US Government more money to fight a losing war, I forecast, I warn, that the United States will lose the next World War it will create. Before the final surrender, the US will use their nuclear arsenal.
If the US starts a war with China, nuclear weapons are inevitable. China has a huge army, but no way to transport it across the Pacific to physically invade the US mainland. The US has ships and transport aircraft, but nowhere near enough manpower to physically invade the Chinese mainland. You can see where such a war must go when the conventional forces amount to a blind mongoose striking at a paralyzed cobra.