Fifth, a resilient sense of optimism. To hear Sanders or Trump, Cruz and Ben Carson campaign is to wallow in the pornography of pessimism, to conclude that this country is on the verge of complete collapse. That’s simply not true. We have problems, but they are less serious than those faced by just about any other nation on earth.

People are motivated to make wise choices more by hope and opportunity than by fear, cynicism, hatred and despair. Unlike many current candidates, Obama has not appealed to those passions.

No, Obama has not been temperamentally perfect. Too often he’s been disdainful, aloof, resentful and insular. But there is a tone of ugliness creeping across the world, as democracies retreat, as tribalism mounts, as suspiciousness and authoritarianism take center stage.

Obama radiates an ethos of integrity, humanity, good manners and elegance that I’m beginning to miss, and that I suspect we will all miss a bit, regardless of who replaces him.