Reverdy Johnson served as U.S. attorney general from 1849 to 1850 under President Zachary Taylor. Johnson also served in the U.S. Senate and as minister to Great Britain but he is best remembered for his constitutional arguments in the Dred Scott case.

Johnson was born May 21, 1796, in Annapolis, Maryland. He graduated from St. John's College, in Annapolis, in 1811 and then read the law with a local attorney. At this time it was common for a person to obtain a legal education by apprenticing with an attorney, performing clerical duties and reading cases. Admitted to the bar in 1815, within two years Johnson had established a practice in Baltimore.

Johnson soon became active in the Whig Party and by 1821 he had been elected to the Maryland Senate. For the next 24 years Johnson balanced his political life with a law practice that concentrated on constitutional law litigation. In 1845 he was elected...