Andrew Johnson as VP

[RJNorton]

Danny, here is what I think is the reason. Many Republicans thought having a loyal Democrat as the Vice-Presidential candidate would strengthen the ticket and help get Abraham Lincoln re-elected. So Hannibal Hamlin was dropped, and Andrew Johnson was added to the National Union Party ticket in 1864. Johnson, a Southerner, had been rewarded for his loyalty to the Union. When the Southern states seceded, Johnson, a Democrat from Tennessee, was the only Senator from any of those states who remained loyal to the Union and retained his seat in the Senate chamber.