A century and a half ago today, on March 6, 1857, the U.S. Supreme Court delivered its decision in the case of Dred Scott v. John F. A. Sandford. Scott was a Missouri slave, and Sanford (whose last name was misspelled in the court papers) was a New York businessman who had custody of some family property, including Scott and his wife and two daughters. Back in 1846 Scott (along with his family) had sued for freedom on the grounds that his previous owner, an Army surgeon, had lived in the state of Illinois and the territory of Wisconsin for...