The main reason why <span>Abe Lincoln called the Emancipation Proclamation a "military necessity" in the last section of his speech is because he wanted to show the American people that without issue of slavery dominating the South, the South would be more willing to cede victory to the North. </span>
Colonialism/Imperialism added to the beginning of the conflict as the dispute between the powers became dainty because of the way that there were relatively few areas/nations on the planet left to colonize, implying that nations would be compelled to go after the current settlements that stayed to extend