In the past, store clerks tried to make sure that children did not look at or buy the pornographic magazines on their store’s shelves. Indeed, pornography was difficult to obtain, and young people had to search hard to find it. But today, a child can access scores of pornographic images in the comfort of his or her own bedroom with a few clicks of a mouse.

The Internet has been largely unregulated, with the exception of one attempt in 1996 to stop the proliferation of pornography in cyberspace. A portion of the Telecommunications Act of 1996, called the Communications Decency Act (CDA), made it illegal to disseminate “indecent” material over the Internet. Supporters of the CDA contended that it was important to crack down on cyberporn in order to protect children, who increasingly have unlimited access to computers and...