On last week's episode of Unsupervised Learning, Razib spoke with Alex Nowrestah, a vice president at the Cato Institute and a strong advocate for expanding legal immigration. This week, he turned to the other side of the debate with Jason Richwhine, a resident scholar at the Center for Immigration Studies and a vocal supporter of sharply reducing immigration.

Richwine earned undergraduate degrees in mathematics and political science from American University, and later a Ph.D. in public policy from Harvard. Before joining CIS, he served as deputy director of the National Institute of Standards and Technology and worked as a senior policy analyst at the Heritage Foundation.

The conversation begins with an overview of the dramatic swings in U.S. immigration policy under Biden and Trump. Both note the surge of the foreign-born population in the early 2020s, with the unauthorized share now estimated at 15-16 million. Richwine faults Biden for lax border enforcement and the abuse of parole programs, and points to the comparative effectiveness of Trump's Remain in Mexico policy. He also presses the case for a moratorium, arguing that even legal immigration must be scaled back to sustainable levels. Razib and Richwine weigh the economic and cultural consequences of high-skilled immigration and close by considering whether meaningful reform is politically possible in the years ahead.