The idea of the peacemaker destroying earth in the name of peace has an ironic humor to it. You can't just say "take them out off the picture" and do it. Especially Earth. Even if you could you'd never hear the end of and your name would be something like Satan's Butcher. Peace would be a hopeless venture. You need to hint a small bit of corruption in him before he does this. Just rewrite 'if I can't none can', but make it more hidden and sound like a person with a bit of poetry in his heart instead of a five year old.
I have a copy of the story and will start today.