But what about a big war where the nation has to put all resources into the war effort?USA will lose that war. Let's hope it doesn't happen.
The only "big" wars we've fought (Revolutionary, 1812, Civil, WWII, arguably WWI) have seen us build up a military from among the citizenry, for wars in which citizens mostly believed. There was always initially huge turnover among the officer class, as large numbers of colonels and generals selected by wealth, seniority, and politicking were replaced by men of broader experience who could lead soldiers to win in battle. There was steady improvement in munitions over the course of those wars, as general techniques of American craft and industry were focused on the requirements of war. Perhaps most importantly, soldiers and sailors came from every American family at every level of society. Also, those armies won those wars.
The standing army we have now has none of those characteristics. It spends vast sums in opaque fashion on increasingly specialized and fragile "weapons systems". It is saddled with an immense sclerotic immovable officer class. It shamelessly markets in misleading fashion to ensnare young people with limited options for its rank and file. Also, though it occasionally accomplishes a police action, the permanent American military loses all the "small" wars in which it engages, while slaughtering millions of innocents.