US district judge George Daniels, in a 45-page opinion, rejected Saudi Arabia’s effort to claim sovereign immunity, saying that while the kingdom “attempts to offer seemingly innocent explanations or context, they are either self-contradictory or not strong enough to overcome the inference” that Saudi Arabia employed two men to assist the hijackers involved in the attacks.

Daniels found that the plaintiffs, the families of the 9/11 victims, offered credible evidence that two men, Omar al-Bayoumi, an accountant for a Saudi aviation company, and Fahad al-Thumairy, a diplomat stationed in the Saudi consulate in Los Angeles, had a role in assisting the hijackers.

Daniels said it was “more likely than not” that there was “some connection” between the employment of Bayoumi and Thumairy by Saudi Arabia and the assistance they allegedly provided to the hijackers who lived in the US.

He added that the evidence presented by the plaintiffs “casts doubt” on whether Bayoumi was merely sent to pursue studies in the US, as lawyers for the Saudi government claim.

“By getting himself involved into the hijackers’ preparation for a terrorist attack, Bayoumi appears to have done much more than what a typical accountant or data processing technician would do,” Daniels wrote, referring to what his official job titles were.

Daniels did not make any decision on Saudi Arabia’s potential culpability.

Saudi Arabia can still appeal Daniels’ decision or reach a settlement with the victims’ families to prevent the case from going to trial.

Saudi Arabia has long attempted to quash the case. The kingdom is pursuing liberalising social reforms under Crown Prince Mohammed bin Salman. He has curbed the power of the religious police and has tried to lure investment firms and tourists to the country.

At the same time, the 39-year-old crown prince has cracked down on any form of political dissent.

Daniels’ decision was welcomed by lawyers and other representatives of the 9/11 victims’ families.

“Today’s decision is another powerful step toward justice,” Terry Strada, the chair of a coalition representing victims’ families and survivors, stated.

Almost 3,000 people were killed in the 9/11 attacks. The victims’ families and survivors have waged a 23-year legal battle to take Saudi Arabia to trial over the attack. The Gulf state is one of the world’s largest oil exporters and home to a sovereign wealth fund valued at over $1 trillion.

The Saudi Public Investment Fund (PIF) owns approximately $20bn in US-listed stocks alone, not including real estate and other investments.

The decision by Daniels was made possible because of a 2016 law passed by Congress called the Justice Against Sponsors of Terrorism Act, which allowed the 9/11 victims’ families to sue Saudi Arabia.

The law gives a broad scope for foreign governments to be sued in US federal court if they played any role in terrorist attacks that killed Americans on US soil.

It has real-world implications.

Oftentimes, it can be difficult for US courts to enforce their rulings against defendants abroad. The law allows for US courts to seize any Saudi assets held in the US to pay the 9/11 victims’ families if their suit is successful.