NEW HAVEN — In 2015, the graduating class at Yale Law School, as custom has it, elected one of its professors to give the commencement address. And when the day came, the speaker, Daniel Markovits, got onstage and told the students, more or less, that their lives were ruined.

“For your entire lives, you have studied, worked, practiced, trained and drilled,” he declared.

And that rat race was far from over, at least if graduates wanted to maintain their, and their children’s, place in the “new aristocracy” of merit.

“To promote your eliteness — to secure your caste — you must ruthlessly manage your training and labor,” he said.

“To live this way,” he continued, “is, quite literally, to use oneself up.”

The speech turned the audience at the most elite of elite law schools on its ear (even if it likely knocked few off their post-graduation paths). And now Mr. Markovits is taking his message to the masses, with a big new book arguing that the meritocratic ideal has not only fed rampant inequality and hollowed out the middle class, but also t hreatens democracy itself.