Can a year of the misery these creatures suffered replace or bring back even one second of the life Emmett Till did not get to live?
There is no justice without restitution. Material objects stolen can be returned, broken can be replaced. Broken bodies, damaged minds and stolen lives admit of no restitution. Bodies and minds can heal, perhaps - not always. But a stolen life, a life unlived, is lost forever.
There remain, then, only punishment or forgiveness. Harm done by a person who is themself damaged can perhaps be forgiven "for they know not what they do". Punishment is merely sanctioned and justified revenge.
Certainly, these killers suffered after what they had done. But the suffering was in large part either of their own making, or the result of their inadequacy. It does not redress the balance because it was not punishment. The law meant to ensure punishment failed, and it failed because they were white and their victim was not, at a time and in a place where such things were deemed proper.
One may talk of karma, take a kind of shallow comfort in their misery. But the failure of the law, the failure to punish officially, the failure to acknowledge the evil of the act, these must not be forgotten nor forgiven. Even when we have created a world where such things can no longer happen.