John Strode Barbour Jr. (December 29, 1820 – May 14, 1892) was a slave owner, U.S. Representative and a Senator from Virginia, and fought against the United States in the Confederate Army. He took power in Virginia from the short-lived Readjuster Party in the late 1880s, forming the first political machine of "Conservative Democrats", whose power was to last 80 years until the demise of the Byrd Organization in the late 1960s.