Answer:
People of Union were mostly opponents of slavery. The main reason for that is because North (Union states) were mostly industrialized and were not in need of slaves. So, because of that their economy was not based on slaves, but on developed industrial machines. Among the leaders of Union we need to stress a couple of names. First of all, president Abraham Lincoln, creator of Emancipation Proclamation and strong opponent of slavery and to two generals, Ulysses Grant and William Sherman.
Step-by-step explanation:
Northern States that created Union were economically developed and were not basing their development on agriculture, as it was the case with Southern States. That is why people in the North started opposing slavery even before. Political platform of the people of North especially of Lincoln was based on this. No slavery in the country should exist.