Bonhoeffer knows that we may find ourselves deciding between evil or evil. In these situations, we must act, depending upon our own limited understanding of world, and knowing that the ultimate judgement will be God's. This same judgement will be applied to those responsible for the elimination of a terrorist like bin Laden and, I believe, to a father protecting his family by shooting an intruder. I need to think about this some more, but it allows for universal truths (murder is a sin) to apply consistently on earth while preserving hope that God will have mercy on one's soul in heaven.
Even this short article has piqued my curiosity about Bonhoeffer. One more for the reading list.
I'm a sucker for powerful quotes:
"The sword can never bring about the unity of the Church and of faith. Preaching can never govern nations."
“What is worse than doing evil is being evil.”