Could Mitt Romney Really Ban Porn?

Actually not true in this case. A 'freedom of expression' is considered to be a 1st amendment issue or 'freedom of speech'. It can be enforced locally and it is, because
laws differ state to state regarding 'porn'. Here's a little info for you to chew on:In the summer of 1973, the Court decided a group of pornography/obscenity cases that set the standards for the future of pornography. In his Dissent in one of these cases, Justice Brennan wearily admitted:

"Our experience since Roth requires us not only to abandon the effort to pick out obscene materials on a case-by-case basis, but also to reconsider a fundamental postulate of Roth: that there exists a definable class of sexually oriented expression that may be suppressed by the Federal and State Governments. Assuming that such a class of expression does in fact exist, I am forced to conclude that the concept of 'obscenity' cannot be defined with sufficient specificity and clarity to provide fair notice to persons who create and distribute sexually oriented materials, to prevent substantial erosion of protected speech as a byproduct of the attempt to suppress unprotected speech, and to avoid very costly institutional harms."[3]
Unfortunately, this realization came too late and without support from the majority of the Court.

Thus, in 1973, in Miller v. California, Justice Burger announced the second definition of obscenity - the majority position of the Court, and the definition, which, more or less, is still in effect today. It is as follows:

"(a) whether the 'average person, applying contemporary community standards' would find that the work, taken as a whole, appeals to the prurient interest,

(b) whether the work depicts or describes, in a patently offensive way, sexual conduct specifically defined by the applicable state law, and

(c) whether the work, taken as a whole, lacks serious literary, artistic, political, or scientific value."
This holding specifically replaced the old test and also held that community standards could be local rather than national. This change swung the pendulum back toward a more conservative definition of "obscenity" by local, some times rural communities.

As many had complained that these rulings were so vague that they were impossible to comply by those trying to obey the law, the Court set forth examples of what was "hard core", or that which the Court considered obscene and illegal. The Court's list of illegal acts was as follows:

"(a) Patently offensive representations or descriptions of ultimate sexual acts, normal or perverted, actual or simulated.

(b) Patently offensive representations or descriptions of masturbation, excretory functions, and lewd exhibition of the genitals."[4]
Clarifications and Today's Definition

Since Miller, the Court has clarified and explained aspects of the Miller standard:

Jurors are to apply the standards of the area "from which he comes for making the required " decision as the "community standards" for obscenity; [5]

"[A]ppeals to the prurient interest" means that which appeals to "shameful or morbid interests" in sex, but not that which incites normal lust [6] and includes materials designed for and primarily disseminated to a deviant sexual group (for example, sadists) which appeals to the prurient interests of that group; [7]

"[A]verage person " includes both sensitive and insensitive adult persons, but does not include children; [8]

Serious artistic, political, or scientific value, using a national standard, is required for a finding that something is not obscene and a finding of some artistic, political or scientific value does not preclude a finding that a work is obscene.[9]
Additionally the Court has created a sort of middle category of materials – "indecent" materials that are protected speech. Indecent materials are defined as those which show "nonconformance with accepted standards of morality."[10] After reviewing the above, most persons, including lawyers, remain confused about what is and is not legally permissible.