The State governments can if they want. "Campaigning" against tobacco is not supposed to be part of their job any more than "campaigning" against pornography. You act as if every abuse of the government by the left entitles you to an equal abuse of your own.
Pornography is a cancer on society. Livius has the appropriate analogy. If we as a society spend money on tobacco and illegal drug use, it is perfectly good sense to spend money in some measure to stigmatize porn users and prevent its easy access. Perhaps targetting sellers would be another way.
This garbage breaks up families and dehumanizes men and women. Involvement with children is an unspeakable crime.
In a world where homos now have special govt protection in many instances, I can understand a fear the federal government getting involved in another values campaign. But all laws come from someone's values. Why not make laws from values that have been known to nourish life and true love, the kind that sacrifices for another.
In an ideal society, there would be no government and there would be no need for this. Do you live in an ideal society? I thought not. Both anarchy and libertarianism are the governments of Heaven. That is, people are entirely self-motivated because they have subscribed to the right beliefs and ideals, and there is no need for government.
However, for the rest of us, this isn't the case. Government does have an obligation to protect the weak (such as children and even animals) against exploitation, and it also has a responsibility to create conditions that promote the common good.
It would be hard to argue in any way, shape or form that your love of pornography fosters the common good. It's not good for the women in the films you watch, it's certainly not good for the children and even the animals, and in the long run, it's not even good for you. In fact, it's probably worst for you, and gives you a way of looking at life that is probably going to mess you up permanently. So, yes, I'd say the common good is affected and that society should respond.