Texas and 18 other states have recently enacted laws requiring pornography websites to verify the ages of their visitors.

A panel of appeals judges has ruled that Tennessee can begin enforcing a law that requires pornographic websites to verify their visitors’ age as the First Amendment debate rises to the U.S. Supreme Court this week for oral arguments over a similar Texas law.

In Texas, Florida, and more than a dozen other states, users who try to access the world’s largest pornography website are greeted by a surprising sight: a message on a black screen telling them they’re blocked because of the actions of their state legislature.