Exactly. An innocent citizen whose life is taken has had every one of of his constitutional rights violated.
If I recall correctly, the Emancipation Proclamation didn't require court action, in order for government to be considered valid.
Lincoln correctly realized that as President, he had no legal grounds to single-handedly terminate the institution of slavery--but that this had to be done by a constitutional amendment. The Emancipation Proclamation was simply a war powers action by him as the commander in chief of the armies in which he attempted to remove all the slaves from the southern peoples "in rebellion against the United States.” Even in this, Lincoln was very anxious about the legality of his actions. He worded the document very carefully, in legal terms, in his attempt to make it legally binding in future courts of law.
He recognized that the Emancipation Proclamation would have to be followed quickly by a constitutional amendment in order to guarantee the abolishment of slavery.