On May 21, 1796, attorney and statesman Reverdy Johnson was born in Annapolis, Maryland. Johnson represented Maryland, a slaveholding state south of the Mason-Dixon line, as a Whig, in the U.S. Senate from 1845-49 and again following the Civil War as a Democrat from 1863-68. Under President Zachary Taylor, he served as attorney general from 1849 until Taylor's death in 1850. Johnson was considered a brilliant constitutional lawyer and won an 1854 Supreme Court decision in favor of a patent for the McCormick reaper.
Although he personally opposed slavery and emancipated slaves inherited from his father, Johnson represented the slave-owning defendant in the 1857 Dred Scott case in which the U.S. Supreme Court decided that slaves could not be citizens of the United States. The court's decision intensified antislavery sentiment in the North and fed the antagonism that sparked the Civil War. In 1865, the ruling was made obsolete with the ratification of the Thirteenth Amendment prohibiting slavery.