Reparations to decedents of white Union soldiers who died to free them.
They did not die to free slaves. They died to make more people slaves of Washington DC. When the Union armies invaded the South for the first time, they had no intention of doing anything at all about slavery. They intended to keep it in place exactly as it was.
It was almost two years later before the war was made to be about slavery. The war was actually began with the sole purpose of forcing the seceding states back under the control of Washington DC.
That was the only goal when the war began.