Salmon Portland Chase (January 13, 1808 – May 7, 1873) was an American politician and jurist who served as the sixth Chief Justice of the United States from 1864 to his death in 1873. Earlier in his career, Chase was the 23rd Governor of Ohio and a U.S. Senator from Ohio prior to service under Abraham Lincoln as the 25th Secretary of the Treasury. As Secretary of the Treasury, Chase strengthened the federal government, introducing its first paper currency as well as a national bank, both during wartime. Chase articulated the "slave power" thesis, devoting his energies to the destruction of what he considered the Slave Power—the conspiracy of Southern slave owners to seize control of the federal government and block the progress of liberty. He coined the slogan of the Free Soil Party, "Free Soil, Free Labor, Free Men". Chief Justice Chase presided over the Senate trial of Andrew Johnson during the President's impeachment proceedings in 1868.