To be clear: It’s not illegal simply to take $8,000 out of the bank repeatedly.

“The criminal provisions there do have strong mens rea (criminal intent) requirements: The government has the burden to prove that the defendant knew about the reporting requirement and intended to evade it,” said Jim Copland, who directs the Center for Legal Policy at the Manhattan Institute, a right-of-center think tank. “So this is quite unlike many of the regulatory crimes that can ensnare the unsophisticated.”

“Whether a former House Speaker who presided over the Patriot Act’s enactment can show absence of mens rea here, of course, may be doubtful,” he added.

Prosecutions for structuring without any charge of an underlying offense with the money are not unusual, said Peter Djinis, a lawyer focusing on laws against money laundering, who until 2002 was executive assistant director for regulatory policy at the Financial Crimes Enforcement Network, the arm of the Treasury Department that enforces these rules.