I equate the moves of some to limit the Adult industry as very similar to Prohibition in the 20s.
Great Article on the Failure of Prohibition with comparisons to modern equivalants.
Even though there is concern in some quarters about the possible hyperconservative nature of the Supreme Court by the end of a possible second Bush term, I don't believe it will go that far. The lessons of the past are just too obvious for us to repeat them. Even many of those who did not like many of today's vices (porn, gambling, adult clubs, etc) recognize that to outlaw them will only drive the industries underground and thus increase crime.
On ABC Primetime last night they revealed the data gathered in a new sex survey run by the ABC Polling department. According to the results of that poll 30% of Americans have made use of adult videos to enhance their sex life. For those of you counting at home, that is somewhere in the neighborhood of 100,000 people. A significant market to profit from and likely worth the chance of getting caught.
I cannot see law enforcement agencies supporting this idea either. Consider the amount of increased law enforcment to go with new laws like this and thus the necessary increase in budgets. In short, while I see groups out there who will make the attempt, I do not see much success for them in the future.