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By Jean Guerrero

Ms. Guerrero, a contributing Opinion writer, is a journalist and author.

The U.S.-Mexico border is no longer just a line on a map; it is a roaming force, drifting through our cities and ravaging schools, courthouses and workplaces. It has become unmoored from geography, dragging its violence and impunity into the heart of American life.

Once confined to the borderlands, the Border Patrol — with its culture of Wild West impunity — is now operating across the country, joining Immigration and Customs Enforcement in raids far from ports of entry. Gun-toting agents, sometimes in cowboy hats, are treating places like Los Angeles and other cities deep in the United States as if they were lawless outposts on a hostile frontier. ICE, the Border Patrol and other agencies have been deputized to carry the border with them — to enforce its racialized, exclusionary logic wherever they go. It has become routine to see masked agents jump out of unmarked vans to detain people violently, based on their skin color.