The best "advertisement" for a good, solid liberal arts education (including the citizen skills of analytical, logical, careful thinking a la mathematics) might be to simply quote what whose who opposed a liberal arts education (and who also opposed democracy..) had to say, warning against a liberal education, which they said was dangerous to a so-called "well-run" country — "run" by them, presumably. Quote:

"Because a knowledge of letters is entirely indispensable to a country, it is certain that they should not be indiscriminately taught to everyone. A body which had eyes all over it would be monstrous, and in like fashion so would be a state if all its subjects [sic] were learned: one would find little obedience and an excess of pride and presumption...
"It would, indeed, fill France with quibblers more suited to the ruination of good families and the upsetting of public order than to doing any good for the country. If learning were profaned by extending it to all kinds of people...
"It is for this reason that statesmen in a well-run country would wish to have as teachers more masters of mechanic arts than of liberal arts"

Armand Jean du Plessis, Cardinal Duc de Richelieu
Political Testament, c. 1638, part 1, chapter 2
Quoted in an MAA journal.