In northern states, it is illegal to have slaves, but in southern states, it is legal to own slaves. Someone from the northern states start the abolition movement, which call out it is morally wrong to own another human being. And because the different position both side holds about slavery, it leads to the civil war.
Key Event: Gettysburg
This was one of the only two battles that was fought in the North. Lee had invaded Maryland but was pinned down at Antietam Creek by Mclellan, and the victory of Union forced Lee back to the South. After the battle, Lincoln addressed the Emancipation Proclamation, which freed all slaves in areas not controlled by the Union.
End of the war: Appomattox
In this battle, the siege bogged down Grant for three days, and the Confederacy who are in the fortress were split by the Mississippi River which was one of the most important victory in the west
Goals of Reconstruction
This is the turning point of the war. And this battle has the most casualties. General Lee invaded North again and tried to break the Union line for two days; he tries a frontal attack the Union forces but forced to retreat back to Virginia after the " Pickett's Charge". After this battle, South has never get a chance to threaten the North again.
This was the final chapter of the war and Lee's surrender to Grant when he has less than 10, 000 soilders left.
Radical Republican's plan is punish the South by destroying political power of former slave holders, giving African Americans full citizenship and right to vote and passed Wade-Davis Bill.