The issue of slavery in America suddenly became hot in 1854 with the Kansas-Nebraska Act: the act that opened all the territories of the Northwest to slavery and caused the split of the Democratic party and the birth of a new and strong Republican party. On January 1, 1863 the Emancipation Proclamation was issued, it represented a turning point in the war because it aimed to end slavery in all states and also proved to be an important strategic measure. The Proclamation was fundamental for the victory of the Union because it complicated the economic situation of the southern states. In fact, the slaves belonging to the Confederate owners were declared free: many fled to the north and joined the Union army. Following the Proclamation and up to 1865 about 4 million people were freed from the state of slavery. After the death of Abraham Lincoln, amendments XIII (13), XIV (14) and XV (15)to the Constitution of the United States of America were ratified, sanctioning the end of slavery, political equality and citizenship of people of color.