Prior to the Civil War, America was divided into 5 main categories:1. The
Radical Republican North that said slavery is wrong - end it now.
2. The
Moderate Republican North that said slavery is wrong - transition out of it orderly over time.
3. The
Practical Amoral Neutral that only cared about the economy - jobs, tariffs and taxes.
4. The
Moderate Democrat South that said slavery is wrong, but we have to live with it - just have it be rare and few, and treat your slaves nice.
5. The
Extreme Democrat South that said slavery is good - let's expand it into new States and force Northerners who are morally opposed to slavery to participate in it through the Fugitive Slave Act of 1850.
When the Civil War started, it looked as if the Confederate South would win quickly.
Lincoln faced draft riots, and ruled by decree, enacting martial law and suspending habeas corpus so that the government could arrest anyone without a warrant.
In 1862, the Confederates defeated Union forces at the Second Battle of Bull Run and crossed the Potomac River into Maryland.
On September 15, 1862, Confederates captured Harper's Ferry, taking over 12,000 Union prisoners.
The Confederate drive halted when Lee's Special Order 191 was misplaced and found by Union troops.
This allowed Union forces to gain an advantage at Sharpsburg, Maryland, resulting in the Battle of Antietam, September 17, 1862, the bloodiest day of fighting in American history with over 23,000 casualties.
Five days later, September 22, 1862, Lincoln met with his cabinet to draft the Emancipation Proclamation, commenting:
"The time for the annunciation of the emancipation policy can no longer be delayed.
Public sentiment will sustain it, many of my warmest friends and supporters demand it, and I have promised God that I will do it."
When asked about this, Secretary of the Treasury Salmon P. Chase wrote that Lincoln replied:
On DECEMBER 1, 1862, President Lincoln gave his Second Annual Message:
"In giving freedom to the slave, we assure freedom to the free...
We shall nobly save - or meanly lose - the last, best hope of earth. Other means may succeed; this could not fail.
The way is plain...a way which if followed the world will forever applaud and God must forever bless."
The President, claiming Commander-in-Chief powers during war time and declaring the South a war-zone, issued the Emancipation Proclamation to free slaves held in the States at war.
The Emancipation Proclamation did not attempt to free slaves held in the North as those States could not be considered part of the rebellion and therefore there were no grounds for the President to try to overrule their State governments.
The Emancipation Proclamation was considered an unconstitutional usurpation of power by the President, so Lincoln undertook to have Congress end slavery through the proper constitutional process by passing the 13th Amendment.
This required 2/3's of Congress to approve it, as portrayed in Steven Spielberg's movie, Lincoln (2012).
The 13th Amendment was passed in the Senate on April 8, 1864, with all 30 Republicans and 4 Democrats voting in favor.
The 13th Amendment was passed in the House on January 31, 1865, with all 86 Republicans voting in favor together with 15 Democrats, 14 Unconditional Unionists, and 4 Union men.
Voting in the House against the 13th Amendment were 50 Democrats and 6 Union men.
Though not necessary, Lincoln, the first Republican President, added his signature to the 13th Amendment after the words "Approved February 1, 1865."
Though slavery was officially abolished, Democrats in South States passed Black Codes and Jim Crow Laws, and created racial vigilante organizations.
Republicans responded by pushing to enlarge the Federal Government's power more with the 14th Amendment in 1868, ensuring civil rights for freed slaves; and the 15th Amendment in 1870, banning racial voting restrictions.
Lincoln had stated earlier at Independence Hall, Philadelphia, February 22, 1861:
"The Declaration of Independence gave liberty not alone to the people of this country, but hope to all the world for all future time.
It was that which gave promise that in due time the weights would be lifted from the shoulders of all men, and that all should have an equal chance...
This is the sentiment embodied in the Declaration of Independence...I would rather be assassinated on this spot than surrender it." 
