Well, you can read the Supreme Court opinion to find out exactly why: https://supreme.justia.com/cases/federal/us/554/570/#tab-opinion-1962738 https://supreme.j

Well, you can read the Supreme Court opinion to find out exactly why: https://supreme.justia.com/cases/federal/us/554/570/#tab-opinion-1962738 https://supreme.justia.com/cases/federal/us/554/570/#tab-opi... In short, the clause is there as a justification/motivation, and not a precondition, for the right to bear arms.