The United States Senate fails to convict President Andrew Johnson by one vote.

The United States Senate is a chamber of the bicameral United States Congress; it is the upper house, with the U.S. House of Representatives being the lower house. Together, the Senate and House have the authority under Article One of the U.S. Constitution to pass or defeat federal legislation.

The impeachment of Andrew Johnson for "high crimes and misdemeanors" was initiated by the United States House of Representatives on February 24, 1868. The alleged high crimes and misdemeanors were afterwards specified in eleven articles of impeachment adopted by the House on March 2 and 3, 1868. The primary charge against Johnson was that he had violated the Tenure of Office Act. Specifically, that he had acted to remove Edwin Stanton from the position of Secretary of War and to replace him with Brevet Major General Lorenzo Thomas as secretary of war ad interim. The Tenure of Office Act had been passed by Congress in March 1867 over Johnson's veto with the primary intent of protecting Stanton from being fired without the Senate's consent. Stanton often sided with the Radical Republican faction and had a good relationship with Johnson.

Andrew Johnson was the 17th president of the United States, serving from 1865 to 1869. The 16th vice president, he assumed the presidency following the assassination of Abraham Lincoln. Johnson was a War Democrat who ran with Lincoln on the National Union Party ticket in the 1864 presidential election, coming to office as the American Civil War concluded. Johnson favored quick restoration of the seceded states to the Union without protection for the newly freed people who were formerly enslaved, as well as pardoning ex-Confederates. This led to conflict with the Republican Party-dominated U.S. Congress, culminating in his impeachment by the House of Representatives in 1868. He was acquitted in the Senate by one vote.