I think the underlying ethos: if you aren’t willing to risk your life for your country, why should you have an opportunity to lead it or get paid by it?
FWIW, I desperately tried to join the Army and the Marines, but had an ear infection as a kid that left me partially deaf (however I’d do basic and a tour of any hell-hole they’d send me even at 56 if it meant being able to vote).
Yes our politicians contain many veterans. Like LBJ and Lindsey Graham. JAGs. Military liers err lawyers.
Coolidge was never in the military, and he was the best President of the 20th century.
Jimmy Carter was in the military. Gerald Ford, the great forger on the Warren Commission, was in the military. G.W. Bush, butcher of millions, was in the military.