Samuel Moyn looks suspiciously like a teenager. The impression is momentarily belied by his impressive résumé: At the age of 45, Moyn is teaching his first semester as a professor of history and law at Yale University, following appointments at Harvard and Columbia. Moreover, even for an adult scholar, Moyn has well-informed views on a startling diversity of topics. Slumped across a chair in jeans and Converse in his Harvard law office last winter, he ricocheted from the French philosopher Emmanuel Levinas (the topic of Moyn’s dissertation and first book) to theories of political economy — something Moyn has devoted more attention to since the 2008 financial crisis — to Jonathan Littell’s 2009 novel The Kindly Ones, which Moyn called "intentionally sickening and an unquestionably brilliant success" in a review for The Nation.

On the other hand, Moyn has a social-media habit rivaling that of most teenagers. 

"It’s more important for you to see Moyn’s Facebook page than the interior of his house," says Thomas Meaney, a former student of Moyn’s at Columbia. "He basically lives there. It’s like he publishes his own magazine." 

On a recent visit to the page, links could be found to an editorial on the ACLU’s defense of white supremacists in the wake of Charlottesville, an abstruse law-review article on global political economy, and a conversation between the New Yorker editor, David Remnick, and the intellectual historian Mark Lilla about Lilla’s new book, The Once and Future Liberal. The comment sections under each serve as a forum for discussion among people who seem to know each other, by byline if not by face, from the middle reaches of academe and publishing. As is common on social media, the discussions tend to converge toward a self-congratulatory consensus, to such an extent that Moyn’s occasional refusal to signal where he stands on controversial articles can be a cause of consternation ("Sam, is this one of those fyi posts? Or an endorsement?" asked one commenter, nervously, under his link to an excerpt of Lilla’s book). Yet Moyn’s range of interests, his volume of activity, and the unusually high erudition of his followers make the page destination reading for an increasingly prominent community of left-liberal scholars. 

 It’s also a good place to start understanding Moyn’s growing influence. At the time we met, Moyn was putting the finishing touches on Not Enough: Human Rights in an Unequal World (Belknap). Due out in the spring, the book promises to cement his reputation as one of the most trenchant critics of "liberal humanitarian" foreign policy. Yet Moyn’s reputation is also tied to his status as a model and magnet for a generation of younger historians and public intellectuals, many of them former students or mentees, who drifted into his orbit during his time in the Columbia history department from 2001 to 2014. ...