The sociologist Louise Seamster discusses America’s student debt crisis and how higher education contributes to the racial wealth gap. : Hey, it’s Ezra. While I’m on paternity leave, we are turning the show over to an all-star team of guest hosts. This week, Tressie McMillan Cottom takes the helm. Tressie is a research professor at U.N.C. Chapel Hill’s I- School. She’s a contributing writer to New York Times Opinion. She’s got a great newsletter you should sign up for.