The U.S. Supreme Court upheld criminal penalties Monday for the promotion of child pornography, ignoring arguments that the law could apply to mainstream movies that depict adolescent sex, classic literature or even innocent e-mails that describe pictures of grandchildren.

The ruling upheld part of a 2003 law that also prohibits possession of child porn. It replaced an earlier law against child pornography that the court struck down as unconstitutional.

The law sets a five-year mandatory prison term for promoting or pandering child porn and does not require that someone possess child pornography. Opponents have said that could make the law apply to movies such as "Titanic" or "Traffic," which depict adolescent sex. Both movies won "best picture" Academy Awards, "Titanic" in 1997 and "Traffic" in 2000.

Click here to read the opinion (pdf).

Justice Antonin Scalia, in his opinion for the court, said the law does not deal with movie sex. There is no "possibility that virtual child pornography or sex between youthful-looking adult actors might be covered by the term 'simulated sexual intercourse,"' Scalia said.

Likewise, Scalia said, free speech protections in the First Amendment to the U.S. Constitution do not apply to "offers to provide or requests to obtain child pornography."

Justice David Souter, joined by Justice Ruth Bader Ginsburg, dissented. Souter said promotion of images that are not real children engaging in pornography still could be the basis for prosecution under the law. Possession of those images, on the other hand, might not be prosecuted, Souter said.

"I believe that maintaining the First Amendment protection of expression we have previously held to cover fake child pornography requires a limit to the law's criminalization of pandering proposals," Souter said.

The 11th U.S. Circuit of Appeals struck down the provision. The Atlanta-based court said it makes a crime out of merely talking about illegal images or possessing innocent materials that someone else might believe is pornography.

In the appeals court's view, the law could apply to an e-mail sent by a grandparent and titled "Good pics of kids in bed," showing grandchildren dressed in pajamas.

In 2002, the court struck down major provisions of a 1996 child pornography law because they called into question legitimate educational, scientific or artistic depictions of youthful sex.

Congress responded the next year with the PROTECT Act, which contains the provision under challenge in the current case.

Authorities arrested Michael Williams in an undercover operation aimed at fighting child exploitation on the Internet. A Secret Service agent engaged Williams in an Internet chat room, where they swapped nonpornographic photographs. Williams advertised himself as "Dad of toddler has `good' pics of her an me for swap of your toddler pics, or live cam."

After the initial photo exchange, Williams allegedly posted seven images of actual minors engaging in sexually explicit conduct. Agents who executed a search warrant found 22 child porn images on Williams' home computer.

Williams also was convicted of possession of child pornography. That conviction, and the resulting five-year prison term, was not challenged.