George Conway III has been cataloguing the reverberations of Morrison v. National Australia Bank ever since he successfully argued the case at the U.S. Supreme Court in 2010, persuading the court to rein in the extraterritorial reach of U.S. securities law. Since then the Wachtell, Lipton, Rosen & Katz partner has seen the decision used to curtail all sorts of claims involving overseas conduct, from antitrust to racketeering.

Now Conway is looking to ensure that Morrison’s effects also extend to criminal conduct–an area where the ruling’s holding against extraterritorially has butted up against a much older Supreme Court decision. On Tuesday Conway and his colleagues at Wachtell filed a 30-page amicus brief at the U.S. Court of Appeals for the Second Circuit for the New York City Bar Association, arguing that federal prosecutors misinterpreted both Morrison and the Supreme Court’s 1922 decision in United States v. Bowman while pressing charges that a group of brokers fraudulently manipulated a sub-market of the London Stock Exchange.

The Wachtell lawyers dispute the government’s assertion that under Bowman, the presumption against extraterritoriality doesn’t apply to criminal securities fraud claims. “In civil cases, as the Government does not dispute, Morrison governs, and Section 10(b) only applies to domestic transactions,” the brief states. “[T]he Government’s assertion that Morrison does not apply to criminal charges brought under Section 10(b) contradicts a simple and commonsensical principle of statutory interpretation: the text of a statute can have only one authoritative meaning.”

Conway was unavailable to comment on Wednesday. “We hope our brief speaks for itself and we look forward to the argument and seeing what the court does,” said Wachtell partner John Savarese. Tuesday’s filing notes that members of the City Bar’s Special Committee on White-Collar Crime who are employed by the federal government recused themselves from the decision to submit the brief. The government’s Second Circuit brief is due Sept. 28.

Having the architect of Morrison, the Wachtell firm, and the City Bar making that argument has got to be good news for defendant Ross Mandell, who received a 12-year sentence in May in the underlying case before U.S. District Judge Paul Crotty in Manhattan. Mandell’s lawyer, Matthew Brissenden of Garden City, N.Y., argued in his opening appellate brief that the government sensed that its case against Mandell was “on shaky legal ground” after Morrison because it centered on allegations that mostly overseas investors were defrauded in overseas trading. “Despite the clear dictates of the Morrison decision, the lower Court refused to exclude evidence relating to foreign transactions, or even to instruct the jury on the need to find a domestic, as opposed to foreign, securities transaction,” Brissenden wrote.

When we reached Brissenden on Wednesday, he suggested that the appeal shouldn’t just interest white-collar and securities litigators. “I think it’s an important issue–one that has potential implications beyond [SEC rule] 10(b) 5,” Brissenden said. “At some level it raises the question of whether all criminal statutes. . .are subject to the assumption against extrateritoriality. We’ve argued that the answer here should be an emphatic yes.”

Note: Due to an editing error, an earlier version of this story failed to clearly report that Tuesday’s brief was filed for the New York City Bar Association. We regret the error.