Washington — Free speech versus online pornography heads back to the U-S Supreme Court today. At issue is how to protect Web-surfing children from smut that adults can legally see and buy.

Justices will take a second look at legislation called the 1998 Child Online Protection Act — which makes it a crime for commercial Web sites to knowingly place material”harmful to minors” within their reach.

The American Civil Liberties Union claims the law violates the First Amendment guarantee of free speech. The A-C-L-U has challenged the law on behalf of online bookstores, artists and others, including operators of Web sites that offer explicit how-to sex advice or health information.

The Bush administration argues tougher laws are needed because kids can easily access free “teasers” to adult Web sites without actually entering the site.