Recently, Barack Obama — a Demosthenes determined to elevate our politics from coarseness to elegance; a Pericles sent to ameliorate our rhetorical impoverishment — spoke at the University of Michigan. He came to that very friendly venue — in 2012, he received 67 percent of the vote in Ann Arbor’s county — after visiting a local sandwich shop, where a muse must have whispered in the presidential ear.