[munk-a]

It might be a violation of the first amendment, but I think that'd be unlikely.

Access to such is already heavily restricted based on the viewers age and the content (including the actors age) and that seems to be generally socially acceptable. I think that the "important" part of the first amendment is usually focused on government control of speech that is made in opposition to the government, this doesn't appear to violate that in any way so I'd guess that the supreme court would probably be okay with this law from a purely first amendment perspective.

A more applicable law would seem to be Article 1 Section 8 (the interstate commerce clause) but that is also pretty weak - I believe that certain states already have widely differing views on adult content so even that might not stand up.