It is back to the drawing boards for those in Congress seeking to protect children from the effects of pornography on the Internet.
In an important First Amendment ruling Tuesday, the US Supreme Court ruled that the Child Online Protection Act (COPA) violates free-speech principles. The vote was 5 to 4.
The high court said the 1998 law was not tailored narrowly enough to children. Instead, it restricted materials and information that adults have a constitutional right to receive without government interference or censorship, the court said.
"The government has failed, at this point, to rebut the plaintiff's contention that there are plausible less restrictive alternatives to the statute," writes Justice Anthony Kennedy for the majority.
The decision is a setback to those seeking to counter an explosion of sexually explicit content on the Internet.
It is a major victory for free-speech advocates, who say parental supervision and privately purchased filtering software are more effective ways to address the problem.
On a broader level, the decision is significant because congressional efforts to protect children from online pornography represent the cutting edge of government attempts to regulate cyberspace.
A debate has long raged over whether the Internet should be treated as an unrestricted free market of ideas and images or more as a government-controlled information "superhighway" complete with speed limits, tolls, and cyber traffic cops.
With this ruling, the nation's highest court has declined to endorse a role for the US government as a cyber traffic cop, at least in this context.
The ruling does not strike down the law as unconstitutional. Rather it upholds a lower-court injunction blocking the implementation and enforcement of COPA. The majority justices remanded the case back to the lower courts to conduct a full trial on the constitutionality of the law.
In a dissent, Justice Stephen Breyer says he would uphold the law as constitutional since, in his view, there is not currently a less restrictive way to protect children from Internet pornography.
"The act ... risks imposition of minor burdens on some protected material - burdens that adults wishing to view the material may overcome at modest cost," he writes.
COPA is the second Internet pornography law deemed unconstitutional by the high court in seven years. In 1997, the justices invalidated the 1996 Communications Decency Act on free-speech grounds. COPA was an attempt to rewrite the CDA to comply with the free-speech concerns raised by the high court.
But the majority justices said Tuesday that the effort fell short.
"It is important to note that this opinion does not hold that Congress is incapable of enacting any regulation of the Internet designed to prevent minors from gaining access to harmful materials," Justice Kennedy writes.
He adds that the opinion does not foreclose the lower courts from concluding at trial that COPA is the "least restrictive alternative available" and thus complies with the Constitution.
Kennedy was joined in his majority opinion by Justices John Paul Stevens, David Souter, Clarence Thomas, and Ruth Bader Ginsburg.
In addition to Justice Breyer, those dissenting were Chief Justice William Rehnquist and Justices Antonin Scalia and Sandra Day O'Connor.
COPA sought to outlaw from general viewership on the Web any sexually explicit material that is "harmful to minors." Violators were subject to six months in prison and fines of up to $50,000 per violation per day for as long as the violation persisted.
The law was designed to encourage website operators to place all such sexually explicit material behind an adult "screen" on the website, with access to the material permitted only through age verification mechanisms like credit cards or adult identification cards.
The law was challenged on First Amendment grounds immediately upon passage and has never been enforced. A federal judge has twice struck down the law on free-speech grounds. A federal appeals court has also twice struck down the law.
For a content-based regulation of free speech, courts are bound by prior precedent to apply the most demanding test to determine whether it complies with free-speech principles.
To uphold such a law, the court must find that the government has a compelling interest justifying any First Amendment violation. In addition, the law must be narrowly tailored and use the least restrictive means to achieve the government's goal.