Understanding the Constitution: How States May Respond to Illegal Immigration—Part IV

This Part IV examines a particularly thorny problem: To what extent may the federal government interfere when states exercise their defensive war powers?

Illegal immigrants wait to climb over concertina wire after they crossed the Rio Grande and entered the United States from Mexico, in Eagle Pass, Texas, on Sept. 23, 2023. Eric Gay/AP Photo

Commentary

Part I of this series showed that the unauthorized mass migration into states at the Southern border qualifies as an “invasion” as the Constitution uses the term. That part also pointed to a constitutional canard—the false claim that federal power over war, immigration, and foreign commerce is “exclusive” and that the states have no authority over those subjects whatsoever.