Each and every amendment in the Bill of Rights is important, but the the Second Amendment is the most important because it guarantees that the others will not be taken away. Once the right to own firearms is eliminated, eliminating all other rights (such as the Freedom of Speech) will be a piece of cake. If that happens, what are you going to do? Protest? You certainly can't resist. All you can do is watch it happen. The Second Amendment is our insurance policy against this. It's been working quite effectively for over 200 years.