As the case of the Massachusetts 54th reminds us, African-Americans had to fight for the right to fight, and then fight for equal rights even within the Union Army. Shortly after the now-famous engagement at Fort Wagner, in which the 54th took part, President Lincoln, reacting to Confederate enslavement and murder of Black Union troops, ordered reprisal in kind against Southern prisoners.
When I wrote about the anniversary last year, I was struck (among other things) that the Union would take such a strong stand, even as it did not offer its Black soldiers equal pay and equal opportunity for advancement. Although the retaliation order was never fully implemented, it highlights with unusual clarity the nature of the conflict, and it continues to prompt moral reflection on the nature of war.
Here is the original post, "Abraham Lincoln's Rules of Engagement."
To flesh out this year's post, here is one contemporaneous report on the grim evolving policy, culminating in Lincoln's new order:
The law of retaliation is formally announced by both the National and the Confederate authorities. Two Confederate officers were executed in Tennessee, June 9, by order of General Rosencrans, as spies found within our lines. The Confederates chose by lot, from among our prisoners at Richmond, two officers, and set them apart for execution, when ordered, in retaliation. Two officers of the enemy in our hands were then placed in close confinement, to be executed if the threats of the enemy were carried out. President Lincoln has also issued a proclamation declaring, in effect, that no distinction will be recognized in the treatment accorded to our white and colored troops who may be captured by the enemy. Every case of ill-treatment will be retaliated in kind: hanging for hanging, shooting for shooting, imprisonment for imprisonment. If a colored soldier, taken prisoner, is sold into slavery, a Confederate prisoner will, in return, be confined at hard labor in some prison until the colored prisoner is set free.
(Harper's New Monthly Magazine, September 1863, p. 559)