At issue is how to interpret a 2016 federal law that gives victims of international terrorism and their survivors the “broadest possible basis” to sue those who aided and abetted terrorists.
Washington attorney Seth Waxman, representing Twitter, said the court should dismiss the lawsuit against the social media firm on the grounds that the site did not give “substantial assistance” to Islamic State.
But some justices sounded open to allowing lawsuits against Google, Facebook or Twitter for giving a platform to terrorists.
“You’re not liable for providing a platform that you knew [terrorists] were using to recruit people and to help arrange other terrorist acts?” Justice Sonia Sotomayor asked dubiously.
The complaint alleged Islamic State had openly maintained accounts on YouTube, Facebook and Twitter, and used them to recruit thousands of new members.
Justice Elena Kagan said Twitter was sued because it provided a platform that allowed Islamic State to communicate with its members and recruit new ones. Moreover, the social media firms were aware of the activity because they had been repeatedly warned by government officials.
Justice Clarence Thomas — who also sounded skeptical of Twitter’s argument — asked its attorney about the meaning of aiding and abetting.
“I assume you would agree that if I had a friend who was a mugger, a murderer and a burglar — but other than that a good guy — and I loaned him a gun, but not knowing and not wanting to know what he was going to do with it, that I possibly could be aiding and abetting?”
No, Waxman told Thomas, not unless there was more evidence that you knew your friend was about to commit a crime.
Waxman seemed to make more headway by warning of the consequences of a ruling that would open the door to such lawsuits.
Noting that social media companies serve hundreds of millions of users in this country, he said “every time there is a foreign terrorist incident, every one of them could be liable for treble damages,” he said.
In addition to social media firms, he added, banks, cellphone providers and other businesses could be alleged to have aided a terrorist.
Deputy Solicitor Gen. Edwin Kneedler, siding with Twitter, agreed the suit should be dismissed because there was no evidence that the social media site deliberately aided terrorists.
He said it would be a mistake to allow broad and costly lawsuits against businesses that serve hundreds of millions of people. Under such a rule, even charities and humanitarian groups could be sued for aiding terrorists, he said.
The case of Twitter vs. Taamneh arose from a terrorist attack on the Reina nightclub in Istanbul in 2017. The attacker had been trained by Islamic State, and he shot into a crowd, killing 39 people and injuring 69 others. The American relatives of one victim sued the three major social media sites under the 2016 law.
A federal judge initially dismissed the suit, but the 9th Circuit Court ruled it could proceed.
Justice Brett M. Kavanaugh said he questioned the notion that general businesses serving the public — whether banks, rental car companies or social media sites — would be held liable for aiding terrorists. Thomas said he had the same concern.
Justice Neil M. Gorsuch saw a separate reason to dismiss the suit. The 2016 law refers to aid or assistance to the “person who committed an act of international terrorism.”
The complaint against Twitter describes aid to Islamic State in general, he said, but it does not point to specific evidence involving the attacker who carried out the Istanbul attack.
After nearly three hours of argument, it was not clear how the majority would decide.
On Tuesday, tech industry lawyers were relieved when the justices sounded skeptical of weakening a separate federal law, known as Section 230, that shields websites from being sued over the content posted by others, including by terrorists.
At issue in that case was whether the computerized algorithms used by YouTube to refer users to similar content was protected by Section 230. Several justices suggested the issue was better addressed by Congress.
The justices will meet privately on Friday to discuss both terrorism cases and cast their votes. The decisions may not come until the end of June.