"And if you think disenfranchisement of women, men without significant property, and people of color who also happen to be slaves indicates 'a pretty good assessment of human nature'"
Eric, you left out a significant part of my post: "...it seems to me they had a pretty good assessment of human nature with regard to government." Specifically,  federal government will grow ever more invasive with tentacles reaching into many if not every aspect of corporate and private life if not specifically constrained via enumerated powers. It's true that some of our founding fathers trusted and desired a strong central government, but the fears of the others is strongly represented in our Constitution.
As to my absurd response, it was tongue-in-cheek meant to counter your assignment of absolute responsibility for ALL calamities: "...whatever calamities befall us over the next three to seven years." Of course republicans have no such power, nor do democrats who have spawned their own calamities.