Why did President Lincoln issue the Emancipation Proclamation?

Why did President Lincoln issue the Emancipation Proclamation?
A、Because President Lincoln himself was an abolitionist.
B、Because he wanted to punish the slave-owners in those states which broke away from the union.
C、Because he has no other alternative.
D、Because he realized that in order to win the war, he should make it a just war against slavery so as to rally as many people as possible under the banner of the Federal Government.
【正确答案】：D
【题目解析】：林肯总统发布《解放奴隶宣言》是因为他意识到为了赢得这场战争，他应该使它成为一场反对奴隶制的正义战争，以便在联邦政府的旗帜下团结尽可能多的人。