A legal test that Google’s lawyer told the Supreme Court was roughly “96% correct” could drastically undermine the liability shield that the company and other tech platforms have relied on for decades, according to several experts who advocate for upholding the law to the highest degree.

The so-called Henderson test would significantly weaken the power of Section 230 of the Communications Decency Act, several experts said in conversations and briefings following oral arguments in the case Gonzalez v. Google. Some of those who criticized Google’s concession even work for groups backed by the company.

Section 230 is the statute that protects tech platforms’ ability to host material from users — like social media posts, uploaded video and audio files, and comments — without being held legally liable for their content. It also allows platforms to moderate their services and remove posts they consider objectionable.

The law is central to the question that will be decided by the Supreme Court in the Gonzalez case, which asks whether platforms like Google’s YouTube can be held responsible for algorithmically recommending user posts that seem to endorse or promote terrorism.