The Supreme Court on Friday upheld a Texas law aimed at blocking children under 18 from seeing online pornography.
Nearly half all states have passed similar age verification laws as smartphones and other devices make it easier to access online porn , including hardcore obscene material.
The 6-3 ruling comes after an adult-entertainment industry trade group called the Free Speech Coalition challenged the Texas law. The court split along ideological lines.
The group said the law puts an unfair free-speech burden on adults by requiring them to submit personal information that could be vulnerable to hacking or tracking. It agreed, though, that children under 18 shouldn't be seeing porn.
A leading adult-content website, Pornhub, has stopped operating in several states, citing the technical and privacy hurdles in complying with the laws.