It was important for Lincoln to wait to issue the Emancipation Proclamation because he wanted to ensure that he had the support of the American people, as well as the Union army, before taking such a bold step. He understood that the proclamation would have far-reaching consequences and wanted to make sure that it would have the desired impact on the war effort. By waiting until after a major Union victory at Antietam, Lincoln was able to demonstrate that the proclamation was a strategic military decision rather than simply a moral one.
