The United States Treasury faces a renewed legal challenge that aims to overturn the decision to sanction the crypto mixer Tornado Cash, filed by six individuals backed by the cryptocurrency exchange Coinbase.

A motion for a partial summary judgment was filed on April 5 in a Texas District Court, with the Coinbase-backed plaintiffs moving for the U.S. Office of Foreign Asset Control (OFAC) to settle for the first two counts from its original complaint filed in September 2022.

If granted, it would see the judge rule on some of the factual issues while leaving others for the trial.

The counts claimed OFAC exceeded its statutory powers under the International Emergency Economic Powers Act (IEEPA) and violated the free speech clause of the U.S. Constitution’s First Amendment.

The plaintiffs firstly claimed that OFAC breached a section of the IEEPA that allows the Treasury to take action against the property in which a foreign country or foreign national has an interest.

The motion argued that as the provision only allows the pursuit of property-related action against a foreign “national” or “person,” it doesn’t apply to open-source software.

To strengthen its claim, the plaintiffs argued the 20 or so smart contracts that provide the functionality to Tornado Cash should not be considered property under IEEPA because they cannot be owned:

“An immutable smart contract is incapable of being owned, it is not property and the Department lacks authority under IEEPA and the North Korea Act to prohibit transactions with those smart contracts.”

“No one has the right to alter them. No one has the right to delete them,” they added.

The second main argument put forth is that by banning the open-source code, OFAC is violating the free speech clause of the First Amendment to the U.S. Constitution.

Related: Treasury officials would have done more for national security by leaving Tornado Cash alone

The plaintiffs noted OFAC has the authority to take action against “crypto thieves” like North Korea’s Lazarus Group, but a “total prohibition is thus grossly disproportionate,” as money laundering only accounted for 0.05% of crypto transactions in 2021.

“To ban all uses of Tornado Cash is akin to banning the printing press because a tiny fraction of users might publish instructions on how to build a nuclear weapon,” they added.

The motivation behind the motion is part of a broader effort to restore internet privacy rights for U.S. citizens, the plaintiffs explained. It is the most recent filing since the individuals first sued the U.S. Department of Treasury in September.

The six plaintiffs behind the filing are Joseph Van Loon, Tyler Almeida, Alexander Fisher, Preston Van Loon, Kevin Vitale and Nate Welch. The filing details that most of the group had previously interacted with Tornado Cash.

The legal battle comes as Alexey Pertsev, the creator of Tornado Cash, faces his own troubles in The Netherlands. He has been held since Aug. 18 on a series of money laundering charges.

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