A man with a sword in his hand demands my purse in the highway, when perhaps I have not 12’d. in my pocket; this man I may lawfully kill. To another I deliver 100l. to hold only whilst I alight, which he refuses to restore me, when I am got up again, but draws his sword to defend the possession of it by force, if I endeavor to retake it. The mischief this man does me, is a hundred, or possibly a thousand times more, than the other perhaps intended me, (whom I killed before he really did me any) and yet I might lawfully kill the one, and cannot so much as hurt the other lawfully. The reason whereof is plain; because the one using force, which threatened my life, I could not have time to appeal to the law to secure it: and when it was gone, ’twas too late to appeal. The law could not restore life to my dead carcass: the loss was irreparable; which to prevent, the law of nature gave me a right to destroy him, who had put himself into a state of war with me, and threatened my destruction. But in the other case, my life not being in danger, I may have the benefit of appealing to the law and have reparation for my 100l. that way.
—John Locke. Two Treatises of Government, 1689.
The right of self-defense is immutable. No democratic decision can deny it. In order for the right to be triggered, it is not necessary for an assailant to do actual injury; it is enough that he tries to get his victim in his power or places his victim in justifiable fear for his life.
A woman confronted in a deserted car park at night by a man who makes to grab her need not wait until she is being strangled—she can open fire immediately. A man awoken by a burglar does not have to ask the burglar if he is armed—he can bludgeon the intruder in order to immediately end the uncertain threat to himself and his family.
The right of self-defense belongs not just to victims but to all of humanity. Thus, if a knife-wielding assailant attacks a woman in the street, any person present has the right to immediately kill the assailant in defense of the woman. No kinship or other connection with the woman is necessary—it could be a tourist from the other side of the world.
Self-defense must not exceed its purpose. Once a robber has been shot dead, his getaway driver cannot be chased down and killed. Once the assailant has been immobilized or knocked unconscious, he cannot be executed. Nevertheless, for the most part, the responsibility for the actions taken by innocent parties under inflamed circumstances belongs to the perpetrator of the original crime. Thus, when a bank robber shoots at a security guard and the guard returns fire in a reckless manner, it is unjust to penalize the guard. Unlike the criminal, the guard’s actions were not premeditated and therefore cannot be scrutinized at the same level. He was taken unawares by a deliberate criminal act; the fact that lives were in peril caused surges of adrenaline for which he was unprepared.
It is when we have the opportunity to reflect on our actions that we must be held fully to account for our conduct. The law encourages us to think before we act. It also encourages us to pre-decide important issues by laying down important principles of conduct in our mind so as not to make impulsive criminal decisions. Thus when an innocent person is thrown into a critical situation not of their making, for which they had no time to mentally prepare, it is not fair to judge them as we would a person whose conduct was premeditated. The person who initiated the chain of events must answer for the consequences. As Edmund Burke explained: “It is not fair to judge of the temper or dispositions of any man, or any set of men, when they are composed and at rest, from their conduct, or their expressions, in a state of disturbance and irritation.” (Speech on Conciliation with the American Colonies, March 22, 1775.)
This principle does not excuse a man murdering his wife’s lover—nor any other occasion where a man allows his rage to become unbridled by a non-critical situation. Where a situation is passive, where life and limb are not in peril, a person is not called upon by circumstances to make a split-second decision and cannot claim exculpation.