Pornography - I know the "right" answer, but the government has no business controlling speech.
Which do I trust more - the legislature or the executive - actually neither. While the legislature passes bad laws, almost every bad thing that has been done to an American has been done by the executive. The Legislature itself does nothing.
The FBI or the IRS. No libertarian is enthused by either organization.
Joint chiefs or UN? Well we all know about the UN, but the Joint chiefs are not just 6 4* officers, but a great big bureacracy, almost as bad as any other feral gubmint bureaucracy.
Doctors vs lawyers? In a world where most money for health care is socialized, I am not sure there is a big difference.
Union leaders or business execs - they are both shakedown artists.
Athletes or onwers - a pox on both their houses.
Prisons vs cities - I am a libertarian. We have a higher percentage of our population in prison than any country since Russia closed down the gulags. We have enough prisons already.
Family breakdown - I think it is a symptom rather than a cause.
Environmental problems - I am not an environmentalist, but I do enjoy being able to breath when I drive through New Jersey or Indiana, which you could not do in my childhood - breath in those places, I mean. The libertarian perspective would be that your right to polute ends at my nose, I think
Of what, just out of curiosity?