The Pulitzer Prize-winning journalist Isabel Wilkerson has pointed to 2022 as a milestone for American history, marking the year the country will have existed as an independent nation for as long as the institution of slavery operated on its soil. In observance of Martin Luther King Jr. Day, we’re re-airing Kara’s interview with Wilkerson. This conversation was taped last year, shortly after the events of Jan. 6. In it, the author of “Caste: The Origins of Our Discontents” offers historical context for us to make sense of the present, particularly the country’s seemingly intractable systemic racism. Wilkerson and Kara discuss  the argument at the core of her book — that America’s racial order can be understood as a caste system. And Wilkerson shares  how she saw an invisible ranking system play out in the raid at the U.S. Capitol, arguing that any impulse to move on quickly would be a mistake. Kara will be back on Thursday with a new episode. You can find transcripts (posted midday) and more information for all episodes at nytimes.com/sway, and you can find Kara on Twitter @karaswisher.