All government authority derives from our right to self-defense. Anything we authorize our government to do by force of arms must be something that can be justified as self-defense. Legislating morality, or using the force of government to control the private behavior of others, does not fall into that category. I have many calls challenging me on this, so I think it’s worth clarifying.
One point that is often made is that all laws, even those forbidding rape and murder, legislate morality, but that’s not true. Yes, rape and murder are immoral, but that is not why they are illegal.