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 algorithmicaly recommending user posts that seem to endorse or promote terrorism.

In arguments on Tuesday, the justices seemed hesitant to issue a ruling that would overhaul Section 230.

But even if they avoid commenting on that law, they could still issue caveats that change the way it’s enforced, or clear a path for changing the law in the future.

The Henderson test came about from a November ruling by the Fourth Circuit appeals court in Henderson v. The Source for Public Data. The plaintiffs in that case sued a group of companies that collect public information about individuals, like criminal records, voting records and driving information, then put in a database that they sell to third parties. The plaintiffs alleged that the companies violated the Fair Credit Reporting Act by failing to maintain accurate information, and by providing inaccurate information to a potential employer.

A lower court ruled that Section 230 barred the claims, but the appeals court overturned that decision.

The appeals court wrote that for Section 230 protection to apply, “we require that liability attach to the defendant on account of some improper content within their publication.”

In this case, it wasn’t the content itself that was at fault, but how the company chose to present it.

The court also ruled Public Data was responsible for the content because it decided how to present it, even though the information was pulled from other sources. The court said it’s plausible that some of the information Public Data sent to one of the plaintiff’s potential employers was “inaccurate because it omitted or summarized information in a way that made it misleading.” In other words, once Public Data made changes to the information it pulled, it became an information content provider.

Should the Supreme Court endorse the Henderson ruling, it would effectively “moot Section 230,” said Jess Miers, legal advocacy counsel for Chamber of Progress, a center-left industry group that counts Google among its backers. Miers said this is because Section 230’s primary advantage is to help quickly dismiss cases against platforms that center on user posts.

“It’s a really dangerous test because, again, it encourages plaintiffs to then just plead their claims in ways that say, well, we’re not talking about how improper the content is at issue,” Miers said. “We’re talking about the way in which the service put that content together or compiled that content.”

Eric Goldman, a professor at Santa Clara University School of Law, wrote on his blog that Henderson would be a “disastrous ruling if adopted by SCOTUS.”

“It was shocking to me to see Google endorse a Henderson opinion, because it’s a dramatic narrowing of Section 230,” Goldman said at a virtual press conference hosted by Chamber of Progress after the arguments. “And to the extent that the Supreme Court takes that bait and says, ‘Henderson’s good to Google, it’s good to us,’ we will actually see a dramatic narrowing of Section 230 where plaintiffs will find lots of other opportunities to to bring cases that are based on third-party content. They’ll just say that they’re based on something other than the harm that was in the third party content itself.”

Google pointed to the parts of its brief in the Gonzalez case that discuss the Henderson test. In the brief, Google attempts to distinguish the actions of a search engine, social media site, or chat room that displays snippets of third-party information from those of a credit-reporting website, like those at issue in Henderson.

In the case of a chatroom, Google says, although the “operator supplies the organization and layout, the underlying posts are still third-party content,” meaning it would be covered by Section 230.

“By contrast, where a credit-reporting website fails to provide users with its own required statement of consumer rights, Section 230(c)(1) does not bar liability,” Google wrote. “Even if the website also publishes third-party content, the failure to summarize consumer rights and provide that information to customers is the website’s act alone.”

Google also said 230 would not apply to a website that “requires users to convey allegedly illegal preferences,” like those that would violate housing law. That’s because by “‘materially contributing to [the content’s] unlawfulness,’ the website makes that content its own and bears responsibility for it,” Google said, citing the 2008 Fair Housing Council of San Fernando Valley v. Roommates.com case.

Corbin Barthold, internet policy counsel at Google-backed TechFreedom, said in a separate press conference that the idea Google may have been trying to convey in supporting Henderson wasn’t necessarily bad on its own. He said they seemed to try to make the argument that even if you use a definition of publication like Henderson lays out, organizing information is inherent to what platforms do because “there’s no such thing as just like brute conveyance of information.”

But in making that argument, Barthold said, Google’s lawyer “kind of threw a hostage to fortune.”

“Because if the court then doesn’t buy the argument that Google made that there’s actually no distinction to be had here, it could go off in kind of a bad direction,” he added.

Miers speculated that Google might have seen the Henderson case as a relatively safe one to cite, given than it involves an alleged violation of the Fair Credit Reporting Act, rather than a question of a user’s social media post.

“Perhaps Google’s lawyers were looking for a way to show the court that there are limits to Section 230 immunity,” Miers said. “But I think in in doing so, that invites some pretty problematic reading readings into the Section 230 immunity test, which can have pretty irreparable results for future internet law litigation.”

WATCH: Why the Supreme Court’s Section 230 case could reshape the internet