Few have thought as hard, or as much, about how democracies can preserve individual liberty and national virtue as the eminent political scientist Harvey Mansfield. When it comes to assessing the state of the American experiment in self-government today, his diagnosis is grim, and he has never been one to mince words.

… “I live in a one-party state and very much more so a one-party university,” says the 80-year-old professor with a sigh. “It’s disgusting. I get along very well because everybody thinks the fact that I’m here means the things I say about Harvard can’t be true. I am a kind of pet—a pet dissenter.” …

Consider voting. “You can count voters and votes,” Mr. Mansfield says. “And political science does that a lot, and that’s very useful because votes are in fact countable. One counts for one. But if we get serious about what it means to vote, we immediately go to the notion of an informed voter. And if you get serious about that, you go all the way to voting as a wise choice. That would be a true voter. The others are all lesser voters, or even not voting at all. They’re just indicating a belief, or a whim, but not making a wise choice. That’s probably because they’re not wise.”

By that measure, the electorate that granted Barack Obama a second term was unwise—the president achieved “a sneaky victory,” Mr. Mansfield says. “The Democrats said nothing about their plans for the future. All they did was attack the other side. Obama’s campaign consisted entirely of saying ‘I’m on your side’ to the American people, to those in the middle. No matter what comes next, this silence about the future is ominous.”