gave the weight of his influence to prevent the secession of the state from the Union; and when Trusten Polk was expelled from the United States senate January 10, 1862, for disloyalty, having already served as an officer in the Confederate government, Mr. Henderson was appointed by Lieutenant-Governor Willard P. Hall to fill the vacancy and on the assembling of the legislature was elected to complete the term of Senator Polk which expired March 3, 1863, and was reelected in 1863 for a full term expiring March 3, 1869. He served in the senate as a member of the committee on Post Offices and Post Roads; on the committee on the District of Columbia; on the committee on Finance; on the committee on Expenditures of the Senate; on the committee on Claims; on the committee on Foreign Relations and as chairman of the committee on Indian Affairs. He subsequently originated and organized the Indian Peace Commission in 1867. He was the author of the Thirteenth Amendment to the Constitution of the United States ratified December 18, 1865, providing that slavery should not exist within the United States, and that congress should make legislative appropriation for the enforcement of the article. He was one of the original agitators for that provision for universal suffrage which led to the Fifteenth amendment ratified March 30, 1870, affirming that "the right of citizens of the United States to vote shall not be denied or abridged by the United States, or by any state on account of race, color or previous condition of servitude." He was one of the seven Republican senators who voted for the acquittal of President Johnson on the occasion of his impeachment by the house of representatives, November 25, 1867, and his trial before the senate. In 1869 on retiring from the senate he resumed the practice of law in St. Louis and in 1872 he was the Republican nominee for governor of the state, but at the election he was defeated by Silas Woodson. He was the Republican candidate before the state legislature for United States senator in 1873, but the Democrats being in the majority elected Louis V. Bogy. In 1875 he was appointed by President Grant to assist the United States district attorney in the prosecution of the violators of the revenue laws, known as the "Whiskey Ring," but in December of the same year the president removed him from the office. He presided over the Republican national convention of 1882 and soon after made his home in Washington, District of Columbia. He was elected a regent of the Smithsonian Institution in 1892 and again
