all volunteer professional military; conscription was used briefly only in the Civil War and World War I.

It was reimposed for World War II; intended to be for the war period only. The world was irrevocably changed by WW II and we had become a global power so, for the very first time, the draft was reinstituted in peacetime (1948) after the war and that effectively gave us a quite large standing Army from 1950 until 1973, running about .004 of the population for most of that period with spikes for Korea and Viet Nam (only about seven out of 24) .

From 1973 until 1991, that figure was about .003 -- with no draft.

Compare that to 1930. A 165K Army (including the Army Air Corps) equated to about .0014 of the population. Today with vastly more responsibility it's only about .0017 (with about as many aircraft as has the Air force). That is not a significantly greater number and it doesn't approach the 1950-1991 figure.

I suggest that the deviation in strength and processes is not great and that the real and very significant deviation is the transformation from an inward looking growing nation to a major power with global responsibilities. Given that major change in focus and responsibility -- wanted or not, we have it -- the actual change is miniscule and unavoidable.

The internal US societal changes are, I believe, a different issue that have little bearing on the size and structure of the Army.