Today these patterns favor Republicans because immigrants—like the overall minority population and white college graduates—are concentrated in fewer districts, mostly in urban areas. But each of those three groups is steadily growing as a share of the total population. Immigrants, and minorities more generally, continue to diffuse into new communities beyond the traditional big-city melting pots; dozens of mid-sized heartland cities are now actively recruiting immigrants to reverse population and economic decline.

Over time that diaspora may change the calculus for Hill Republicans who now feel little incentive to question Trump’s immigration offensive. Ali Noorani, executive director of the National Immigration Forum, has spent the last several years carefully building support for immigration reform in red communities among law enforcement, religious leaders, and business executives, an experience he recounts in his compelling upcoming book, There Goes The Neighborhood.

Noorani acknowledges that few congressional Republicans represent communities that today feel directly threatened by Trump’s immigration hard line. “At this moment in time, they remain isolated from the [foreign-born growth],” he said. “But I would argue that the rate of change in the foreign-born population in [many of] these districts is faster than what we are seeing in other parts of the country. The bubble is going to pop in the very near future.”