On September 17 the bloody Battle of Antietam gave Lincoln the opportunity he needed. He issued the preliminary proclamation to his cabinet on September 22, and it was published the following day. 5. The Emancipation Proclamation didn’t actually free all of the slaves. Since Lincoln issued the Emancipation Proclamation as a military measure, it didn’t apply to border slave states like Delaware, Maryland, Kentucky and Missouri, all of which had remained loyal to the Union.