Laws do stop people from doing things. There are some who will not do something simply because it is against the law. The laws may not stop everyone from doing those things you mentioned, but it will stop some. Do you really believe that everyone with car insurance does it because they want to? They simply do it because the law requires it. Drug laws may not directly deter people from doing drugs, but they do stop them by other means. Some people who get in trouble with the law over drugs actually get help that they would probably not seek otherwise. If you think the traffic laws don't affect the behavior of people, I defy you to slow down the next time you are speeding and pass a patrol car. I do believe that under the second amendment that gun laws should not be so restrictive. I believe that anyone set on murder is going to commit it by any means available, so most of the gun laws really only serve to protect the criminals.