The “border” is not a line on the ground, but a tool to enable violence and surveillance.
Karl Jacoby
Karl Jacoby is the Allan Nevins Professor of American History at Columbia University. He is the author of Shadows at Dawn: A Borderlands Massacre and the Violence of History (Penguin, 2008) and The Strange Career of William Ellis: The Texas Slave Who Became a Mexican Millionaire (Norton, 2016), among other works. In 2021–22, he will be the Andrew Mellon Fellow at the New York Public Library’s Cullman Center, where he will be researching a book on the US-Mexico War and its legacies. 
The Never-Ending Frontier?
The US imperialist wars in the Philippines, Korea, Vietnam, and Afghanistan grew from US wars against Indigenous people in the 19th century.