The philosophical literature that defends the right of gun ownership has based its argument on the right of self-defense. This raises the question, what is the basis of the right to use force, even deadly force, in self-defense? What happened to the attacker’s right to life? In the libertarian and proto-libertarian literature, the best-known answer is probably Locke’s forfeiture argument: aggressors, through their rights-violating conduct, forfeit their rights against violence. In the pro-gun-rights literature, the inference from that right to a right to own a gun is typically made in one of two ways. One is to appeal to one’s intuitions about cases: a government that disarms citizens will have violated the rights of those inevitable victims of violence who will die because they were denied an effective means to defend themselves. The other way is by means of a general principle, such as the idea that an “option-right,” like self-defense or free speech, brings with it a “means-right,” which is a right to acquire and use effective means of exercising the option-right. A violation of a means-right is also a violation of the related option-right. There are situations in which only firearms would be an effective means of protecting the innocent. Thus, a government that disarms its citizens is violating their right of self-defense, just as a government that quashes dissent by jamming the cell phone system is violating citizens’ right to freedom of speech.