At the onset of the Civil War, the North is far more industrialized than the South. This industrialization leads to the schism between North and South, mainly because the North does not need slave labor for its economic means to the extent that the South does (though the North very much relied on slave labor, too).

The main motivating factor for a Northern soldier is to keep the Union intact. Many Northern soldiers see the secession as a betrayal of the ideas of the Founding Fathers. Most Northern soldiers believe they are fighting for the nation; their letters say so. Almost 80% vote for Lincoln, who runs on a platform of complete victory in the war.

Not all Northern soldiers (perhaps even few at the beginning) are fighting to end slavery. Some see it as a detestable institution, while others only want to keep the Union intact. Many of them feel betrayed when the Emancipation Proclamation is declared. They do not wish to fight for slaves, who they do not see as equal to them. During emancipation, many soldiers desert rather than fight for slaves. Still others see using freed slaves as a means to end the war more quickly.