Isaac Newton Jenkins (August 19, 1887 – October 16, 1942) was an American attorney, soldier, and political candidate. A perennial candidate for political office, Jenkins ran for office in Illinois many times. He originally ran as a Robert La Follette-aligned progressive member of the Republican Party in the 1920s. Beginning in the mid-1930s, Jenkins publicly espoused antisemitic and fascist views and aligned himself with Adolf Hitler and other Nazis. He associated with other American pro-fascists. He was a figure in the short-lived Union Party, and served as the director of William Lemke's 1936 campaign as the party's presidential nominee.