There are defensible reasons why the American state—or any state—would find King’s ethic hard to live up to. States are violent. The very establishment of government, the attempt to safeguard a group of people deemed citizens or subjects, is always violent. In America, a president is the commander in chief. Anyone who voted for Obama necessarily voted for violence. Furthermore, there is indisputable evidence that violence sometimes works. The greatest affirmation of civil rights in American history—emancipation—was accomplished at gun-point.

But one has to be careful here not to fall into the trap of lionizing killing, of pride in the act of destroying people even for just ends. Moreover, even if nonviolence isn’t always the answer, King reminds us to work for a world where it is. Part of that work is recognizing when our government can credibly endorse King’s example. Sparing the life of Dylann Roof would be such an instance—one more credible than the usual sanctimonious homilies delivered in his name. If the families of Roof's victims can find the grace of forgiveness within themselves; if the president can praise them for it; if the public can be awed by it—then why can't the Department of Justice act in the spirit of that grace and resist the impulse to kill?

Perhaps because some part of us believes in nonviolence not as an ideal worth striving for, but as a fairy tale passed on to the politically weak. The past two years have seen countless invocations of nonviolence to shame unruly protestors into order. Such invocations are rarely made to shame police officers who choke men to death over cigarettes and are sent back out onto the beat. And the same political officials will stand up next January and praise King even as they act contrary to his words. “Capital punishment is against the best judgment of modern criminology,” wrote King, “and, above all, against the highest expression of love in the nature of God.”

Moreover, killing Roof does absolutely nothing to ameliorate the conditions that brought him into being in the first place. The hammer of criminal justice is the preferred tool of a society that has run out of ideas. In this sense, Roof is little more than a human sacrifice to The Gods of Doing Nothing. Leave aside actual substantive policy. In a country where unapologetic slaveholders and regressive white supremacists still, at this late date, adorn our state capitals and our highest institutions of learning, it is bizarre to kill a man who acted in their spirit. And killing Roof, like the business of the capital punishment itself, ensures that innocent people will be executed. The need to extract vengeance cannot always be exact. It is all but certain that a disproportionate number of those who pay for this lack of precision will not look like Dylann Roof.