Read this: Northern leaders agreed that victory would require more than the end of fighting. Secession and Confederate nationalism had to be totally repudiated and all forms of slavery or quasi-slavery had to be eliminated. Lincoln proved effective in mobilizing support for the war goals, raising large armies and supplying them, avoiding foreign interference, and making the end of slavery a war goal. The Confederacy had a larger area than it could defend, and it failed to keep its ports open and its rivers clear. The North kept up the pressure as the South could barely feed and clothe its soldiers. Its soldiers, especially those in the East under the command of General Robert E. Lee proved highly resourceful until they finally were overwhelmed by Generals Ulysses S. Grant and William T. Sherman in 1864–65, The Reconstruction Era (1863–77) began with the Emancipation proclamation in 1863, and included freedom, full citizenship and the vote for the Southern blacks. It was followed by a reaction that left the blacks in a second class status legally, politically, socially and economically until the 1960s.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): What did northern leaders agree on about slavery?
all forms of slavery or quasi-slavery had to be eliminated.