• Debate over how to interpret Second Amendment is fierce
• Precise language of Second Amendment is ambiguous

Just about everybody has an opinion on the Second Amendment—and just about everybody is ready to share it. Just ask a member of the National Rifle Association or a donor to the Brady Center to Prevent Gun Violence whether the Second Amendment protects an individual right to possess guns. Nor can the participants in the gun debate be easily pigeon-holed demographically; both pro- and anti-gun activists can be found in Red States and Blue States, and among Americans of all ages, genders, races, classes, and sexual orientations. Actually, it might be sort of interesting to stage a debate between the Seniors United Supporting the Second Amendment, the Armed Females of America, Pink Pistols, the Million Mom March Foundation, and the Physicians for Social Responsibility.

But then perhaps a debate between these advocacy groups would not be all that helpful in sorting out the meaning of the Second Amendment. These people are all deeply passionate in their views, and one reason for the longstanding vigor of their debate is the fact that the meaning of the amendment itself is not completely clear on its face. Some argue that the only way to get to the bottom of the question is to sort out the "original meaning" of the Second Amendment—that is, what it meant to those who drafted and ratified the amendment, and what the "right to bear arms" was understood to mean during the colonial and revolutionary periods. Perhaps so—and we will try to unravel that history. But for now, let's just look at what the Second Amendment has meant for the last century—or more precisely, what the Supreme Court has said it means for the past 130 years.