In United States v. Williams, a solid majority of the Court found that key provisions of the unfortunately named “Prosecutorial Remedies and Other Tools to end the Exploitation of Children Today Act of 2003” are a model of clarity when compared to past federal efforts to stop the proliferation of child pornography on the Internet.

Unlike Congress’s previous attempts (including the ill-fated federal Child Pornography Prevention Act of 1996), the 2003 Act only prohibits offers to provide and requests to obtain child pornography. Under the Act (which we could refer to by its belabored acronym, “PROTECT,” but let’s not), anyone who deliberately tries to get someone else to believe that he is offering to provide child pornography (regardless of whether his purported child pornography is real or fake, and regardless of whether he is seeking compensation for it) is subject to a mandatory five years in prison. Likewise, anyone who intentionally tries to solicit child pornography is also liable to spend five years in prison.

But what is child pornography, one might ask. Isn’t it impossible to ban such a thing without inadvertently convicting an innocent grandmother who merely emails grandpa what she thinks is a cute picture of her grandson at bath time? And wouldn’t such a law inevitably end up criminalizing even mainstream Hollywood movies such as “Lolita” and “Titanic”?

In a word, the Supreme Court ruled May 19, no.

First, the statute goes to heroic lengths to define in clarifying detail the various types of “sexually explicit conduct” with which it is concerned. Secondly, as Justice Scalia noted in his opinion for the Court’s 7-2 majority, to run afoul of the Act the portrayal of child sex “must cause a reasonable viewer to believe that the actors actually engaged in that conduct on camera.” In other words, it is not enough that such sex is suggested – it must be explicitly portrayed.

Moreover, the Act does not punish either offers to provide or requests to receive pictures of youthful-looking adults posing as children, nor does it ban offers to provide or requests to receive “virtual” child pornography that features computer-generated images of children. “A crime is committed only when the speaker believes or intends the listener to believe that the subject of the proposed transaction depicts real children.”

The Eleventh Circuit, which the Supreme Court has now reversed, worried that the Act is unconstitutionally vague because instances can be imagined in which it might be difficult to know what the defendant’s true belief or intent was. But as Justice Scalia explains, “the problem that poses is addressed, not by the doctrine of vagueness, but by the requirement of proof beyond a reasonable doubt.”

Time will tell, but I think we will find that neither naïve grandparents nor worldly Hollywood producers have anything to fear from this law. I’m also betting that some of the most flagrant child pornography rings will at long last be shut down -- and that the Internet will be a better place without them.