What was the union's goal in the civil war?

Unite the country and end slavery

Explanation:

at the beginning of the war the union wanted to unite the United states and once the Emancipation Proclamation was passed the goal of ending slavery was added

The Union originally wanted to reunite the country, but after the Emancipation Proclamation of 1863, the Union goal changed to include the abolition of slavery. The Confederacy had the same goal throughout the war: to incorporate all slave states and secede from the Union, survive, and defend its territory.