It's impossible to keep it from every happening but it will definitely lower crime rates in the US! Obviously, stricter gun control laws will make it harder for criminals to get guns. A lot of people don't understand what gun control laws mean. They don't mean "get rid of all guns" they mean "make sure sane people have guns, not mentally ill or unstable people." So when conservatives say "your taking away my freedom and violating the second amendment!" they are wrong UNLESS they know that they are unstable and won't be able to get a gun, if they are responsible and sane then nobody is stopping them from getting a gun. Also the second amendment refers to the militias, not common citizens. Also a lot of criminals are not that smart, so if you make it harder for them to do something they are more likely not to do it. Lastly, looking at other countries with stricter gun control laws, like Australia, you can see that after they passed strict gun control laws their crime rate dropped by more than 55%. You'd think these statistics would be proof enough that gun control works.