SALT LAKE CITY (AP) — Utah is a step closer to requiring all cellphones and tablets sold in the state to automatically block pornography after Utah Gov. Spencer J. Cox signed legislation Tuesday that critics call a significant intrusion of free speech.

Cox has said the measure would send an “important message” about preventing children from accessing explicit online content. The proposal is the latest move in Utah’s legislative campaign to curb the availability of porn.

The measure won’t go into effect unless five other states enact similar laws, a provision that was added to address concerns that it would be difficult to implement.

The American Civil Liberties Union of Utah said the constitutionality of the bill was not adequately considered and that it will likely be argued in court.

“This is another example of the Legislature dodging the constitutional impacts of the legislation they pass,” ACLU attorney Jason Groth said.

Critics of the measure, including adult film star Cherie DeVille, have requested Cox veto the measure because it could violate the First Amendment rights of Utahns.

Cox has said he isn’t as worried about Constitutional concerns because the proposal won’t be immediately enacted.

Rep. Susan Pulsipher, the bill’s sponsor, said she was “grateful” the governor signed the legislation. She expressed her hope that this will help parents keep their children from unintended exposure to pornography.

She asserts that the measure passes Constitutional muster because adults can deactivate the filters, but experts said it still raises several legal concerns.

Supporters argue the restriction is a critical step to help parents keep explicit content away from kids — especially as more children have their own electronic devices.