I suspect if you cut the military budget 50%, you might well be able to reduce taxes.
Any discussion of "reasonable levels" of federal income tax rates would have to look at the *effective* tax rate after all the various deductions and special cases are considered. It is common to say "look, they paid NN% back in 1960, let's go back", but generally those comparisions are looking at the notional marginal rates, and not what *actually* got paid after all the dust settled. I know though it is a handy marketing slogan.