The way liberals argue about gun control is to refer to the gun, not the person, as the criminal. This gives them emotional license to regulate and ban guns or magazines however they want, because anyone in favor of the gun rights is therefore in favor of the criminal. This tactic of demonizing and disregarding a political argument is designed to effectively shut down all opposition to liberal perspectives on the issues. If you identify, for example, the conservative position with the criminal’s position, you’ll never even consider their argument for fear you’ll be identified with the criminal.
This is similar to the gay marriage argument. Liberals refer to gay marriage as a civil right, therefore by that definition if you are against gay marriage you are against a civil right. This again gives them license to treat you and your arguments as bigoted, subhuman, and not deserving of any kind of respect or consideration. This results–intentionally–in scaring away all who might consider the position against gay marriage, but fear to be identified with an idea that is associated with a heinous social sin.
So how do you successfully debate with someone using this kind of tactic? Conservatives have to define the issue right from the beginning. Guns do not commit crimes, people do. Therefore, the argument for gun rights is not to be associated with the side of the criminal. Likewise, gay marriage is not a civil right, it is a lifestyle choice. Therefore, to be against the gay lifestyle is no more heinous than being against any other lifestyle such as that of a smoker or a vegetarian. Conservatives need to redefine the premise in order to win the argument, otherwise real political debates will cease to exist.