The last congressman to represent the National Union Party ended his affiliation with the party in March 1867. Johnson was impeached by the Republican-led House of Representatives in 1868 and was acquitted in the Senate by one vote. Upon the 1869 expiration of Johnson's only term as President, the National Union Party came to an end. The platform adopted at the 1868 Republican National Convention strongly repudiated President Johnson while the platform adopted by the 1868 Democratic National Convention thanked Johnson. Johnson received dozens of votes on the first ballot of the Democratic convention, but the party ultimately nominated Horatio Seymour. Meanwhile, the mainline Republicans decided at their 1868 national convention to use the term the National Union Republican Convention. The 1868 National Union Republican delegates nominated Ulysses S. Grant for President and his running mate Schuyler Colfax for Vice President. In 1872, all reference to Union had disappeared. Historians regard the initial National Union coalition assembled in 1864 as part of the Republican Party lineage and heritage.