Mass deportations. What would actually happen—economically—if the President-elect follows through on promises to deport millions of people from America.We don't have to guess.Today we have two stories from Planet Money's daily podcast, The Indicator. First, the story from another time the US cracked down on immigration with the expressed intent of helping the economy. We look at how that worked out. And then we distill 20 years of research on immigrants and economic growth. What does immigration do for an economy? What types of immigration help? And who benefits?Our most recent newsletter goes into more depth on some of this. Part one of two here. Subscribe to our newsletter here.This episode is hosted by Adrian Ma, Darian Woods, and Wailin Wong. These episodes of The Indicator were originally produced by Cooper Katz McKim and Julia Ritchey, and engineered by Kwesi Lee and Maggie Luthar. They were fact-checked by Angel Carreras and Sierra Juarez. Kate Concannon is The Indicator's Editor.Help support Planet Money and hear our bonus episodes by subscribing to Planet Money+ in Apple Podcasts or at plus.npr.org/planetmoney.