Walker, Robert John, 1801–69, American public official, b. Northumberland, Pa. A lawyer, he practiced for a time in Pittsburgh. In 1826 he moved to Natchez, Miss. As a Democratic Senator (1836–45) from Mississippi, Walker was an ardent advocate of U.S. expansion and became a leader in the drive to annex Texas. James K. Polk made him Secretary of the Treasury (1845–49), and he had an influential voice in government policies. He reestablished the independent treasury system and helped to improve Anglo-American relations (strained by the Oregon dispute) by the Walker Tariff of 1846, a moderate protective tariff that lowered the rates on many items. His financial administration (he was a firm hard-money advocate) is generally considered one of the most able in the history of the Treasury. In Mar., 1857, he reluctantly accepted appointment as governor of Kansas. Walker was committed to Stephen A. Douglas's popular sovereignty theory, and believed that the majority of Kansans favored admission to the Union as a free state. When President Buchanan refused to support Walker's contention that the proslavery Lecompton Constitution (see under Lecompton) was fraudulently adopted and should be put to popular vote, he resigned (Dec., 1857). He subsequently supported the Union in the Civil War and served as a financial agent in Europe. An expansionist to the end, he had a part in the purchase of Alaska.
See biographies by W. E. Dodd (1914, repr. 1967) and J. P. Shenton (1961).