WAGNER, S.D. — Thomas Jefferson, perhaps the greatest rural snob in history, argued that cities are as useful to a republic as sores are to a human body.

Ever since, town and country have been pitted against each other in American politics, with a somewhat unfair rule seeming to govern their duel: It’s acceptable for the country to sneer at the town, but not the other way around.

And yet the border between town and country is blurring in America. Urban farming, methamphetamine use, the local-food movement, the global commodities boom, the diverging family structures of the educated and less- educated, and various other things are making town a lot more like country and country a lot more like town.

When you land in Mitchell, S.D., and make the hour’s drive to Wagner, here is what you see. First, a burial-vault business outside the tiny airport. Then the Kongo Klub strip joint. And then, for miles and miles, farms that coat the rolling hills, wind tickling the green leaves and the leaves trembling with laughter.