Gun control will do little or nothing to prevent terrorism and other crime, but it will adversely affect law-abiding citizens who seek to defend themselves from those criminals. Paris and Brussels have strict gun control. And Chicago, gun murder capital of the USA, has strict gun control. If making guns illegal would cause criminals to stop using guns, then we could stop murder by simply make it illegal to murder people. Oh, wait, I guess we already have that law on the books. Remember, criminals, by definition, don't care about obeying laws, so piling on more laws will not change the behavior of criminals.