History of the Impeachment of Andrew Johnson, President of the United States, by the House of Representatives, and his trial by the Senate for high crimes and misdemeanors in office, 1868

CONTENTS
Little is now known to the general public of the history of the attempt to remove President Andrew Johnson in 1868, on his impeachment by the House of Representatives and trial by the Senate for alleged high crimes and misdemeanors in office, or of the causes that led to it. Yet it was one of the most important and critical events, involving possibly the gravest consequences, in the entire history of the country.
The constitutional power to impeach and remove the President had lain dormant since the organization of the Government, and apparently had never been thought of as a means for the satisfaction of political enmities or for the punishment of alleged executive misdemeanors, even in the many heated controversies between the President and Congress that had theretofore arisen. Nor would any attempt at impeachment have been made at that time but for the great numerical disparity then existing between the respective representatives in Congress of the two political parties of the country.
One-half the members of that Congress, both House and Senate, are now dead, and with them have also gone substantially the same proportion of the people at large, but many of the actors therein who have passed away, lived long enough to see, and were candid enough to admit, that the failure of the impeachment had brought no harm to the country, while the general judgment practically of all has come to be that a grave and threatening danger was thereby averted.
A new generation is now in control of public affairs and the destinies of the Nation have fallen to new hands. New issues have developed and will continue to develop from time to time; and new dangers will arise, with increasing numbers and changing conditions, demanding in their turn the same careful scrutiny, wisdom and patriotism in adjustment. But the principles that underlie and constitute the basis of our political organism, are and will remain the same; and will never cease to demand constant vigilance for their perpetuation as the rock of safety upon which our federative system is founded.