“Dred Scott had a point there.” A statement of this sort is a good ticket to social ostracism. Dred Scott v. Sandford (1857) remains one of the Supreme Court’s most infamous and despised decisions. In it, Chief Justice Roger Taney argued the American founding saw black people as inferior to white people and that slaves were in bondage for their own benefit.

Taney’s opinion justly deserves the deluge of scorn it receives. It got the founding wrong. It got justice wrong. Worse, it helped rend the country temporarily in two. But one lesser-known element of that opinion would help the public frame the debate about the political status of Puerto Rico in relation to the rest of America.