It seemed as though the odds were stacked against him. Since most of the Democrats - Johnson being the exception - had seceded from the United States along with their states, that left the Republicans almost unilaterally in charge, and they were not in a forgiving mood. In their view, Southerners were enemies who should be punished. They were also not particularly thrilled with Andrew Johnson.
First, he was a Democrat from Tennessee, with a "defective" Southern attitude. Second, diplomacy was not his strong suit. As a senator, his open disdain for the powerful plantation owners that populated his state made him many enemies, and as president, his bluntness certainly did not endear him to the opposing party. And third, he was determined to carry out Lincoln's policy of letting the South up easy. This was probably his most fatal flaw.
Johnson disagreed with the Radical Republican approach of stripping Southerners of citizenship and ramming black rights down the South's throat by military force. He vetoed their legislation, known as the Reconstruction Acts, but the Republicans used their supermajority to override his veto. And that's how the rest of Johnson's presidency went: one bill after another, passed over Johnson's veto.
Finally, Congress passed the Tenure of Office Act, which declared that a president could not fire his own cabinet members without Senate approval. When Johnson fired the conniving Secretary of War, Edwin Stanton, for disloyalty, the House of Representatives voted to impeach the president. House Republicans were in such a hurry that they didn't bother waiting for the Articles of Impeachment to be drawn up. The lopsided vote was 126 to 47.
Next, the Senate voted on conviction and removal from office. Although the Republicans held more seats than the two-thirds majority necessary to convict, conviction failed by one vote. The surprise vote that kept Johnson from being removed from office belonged to Kansas senator Edmund Ross, who had been expected to vote against Johnson. Ross's apparent change of heart shocked everyone and eventually cost him his Senate seat.
As for Johnson, after finishing his term as president, he ran for his old Senate seat and won, becoming the only ex-president in history to become a senator. As independent as ever, he held the seat until his death at the age of 66. Twelve years later, the Tenure of Office Act was repealed. The Supreme Court formally declared it unconstitutional 46 years after that, in 1926.
The Republican agenda that Johnson had unsuccessfully opposed turned out to be a failure as far as black rights were concerned. Embittered by what they considered Northern oppression, Southern whites seized the opportunity to take revenge on blacks when Reconstruction ended, leading to the KKK and many atrocities. (More on that next month.)