Why did so many people feel it was necessary to fight in the civil war?

Many people felt it was necessary to fight in the Civil War due to strong beliefs about states' rights, slavery, and national unity. For the Confederacy, the desire to preserve the institution of slavery and maintain their way of life motivated their fight. Conversely, the Union soldiers were driven by the aim to preserve the nation and abolish slavery. These deep-rooted ideological divides fueled the passion and commitment of individuals on both sides.