Rights Versus Consequences
At the heart of this issue is a more general debate: what is the point of making laws? What are we trying to accomplish? Are we trying to protect people's rights? Or are we trying to create good consequences for society?
With this in mind, what is the point of gun policy?
One position is to say that the point of making laws with respect to guns is to bring about good societal consequences. We should pass the laws that, for instance, lead to the fewest number of deaths.
Taking this position, the debate about gun policy becomes a heavily empirical one. That is, the debate focuses on whether allowing people to own guns or prohibiting them results in less loss of life.
Empirical issues are often complicated, and a lot of discussion and research has looked at whether states with right-to-carry laws have lower or higher rates of death by firearm (and, similarly, at whether countries that prohibit gun ownership have lower or higher rates). Does allowing people to own firearms drive murder rates up? Or does it make people safer, because people can defend themselves with guns? These are the sorts of empirical issues that are hotly debated.
But, another position to take is to say that the point of gun policy is to recognize the right of people to live their lives freely (for instance, to have a gun for recreation, hunting, self-defense against crime, to guard against authoritarian government, etc.). Taking this position, it's simply a matter of having laws that leave people free to own weapons, regardless of what consequences might follow -- for instance, in terms of rates of death by firearm.
In practice, we tend to sympathize with both positions. We want our laws to have good consequences, but we're often content to recognize people's right to be free and to choose for themselves how to live, even if the consequences of doing so aren't the best possible.
At what point does the right to be free outweigh good consequences? At what point do bad consequences outweigh individual freedom? Should we prohibit all weapons? Should we permit them all, even including things like grenades and rockets? If we're going to permit some but prohibit others, where is the line drawn?
The 2nd Amendment
In the United States of America, the 2nd Amendment to the Constitution plays a pivotal role in the discussion of gun policy. It states:
A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.
However, the 2nd Amendment is unclear about some crucial issues.
First, it mentions the right of the people to bear "arms". Does that mean any armaments whatsoever, from swords and guns to howitzers, land mines, and nuclear weapons? It seems problematic to allow people to keep and bear things like mortars and chemical weapons, but it's not clear the text rules it out, either.
Second, the amendment doesn't specify what is sufficient to respect the right to bear arms. Does it mean that the government has to allow us to own anything that counts as an armament, or just some things? If the former, then it looks like we should be allowed to own things like howitzers, etc.; if the latter, then couldn't the government prohibit the ownership of everything except, say, swords, and say that our right to bear arms has being respected?
The issue of gun policy involves a variety of thorny issues: the balance of individual rights against societal consequences, the matter of figuring out what policies yield what results, and the problem of interpreting legal texts.
It's not surprising, then, that the debate about gun control and gun rights is so contentious.