Critics of the Trump administration are calling for ex-National Security Adviser Michael Flynn to be prosecuted under a law that has only netted one person in the past 228 years.

Flynn, a retired U.S. general, resigned from his White House post late Monday night after he was exposed as lying to Vice President Pence and the public about his conversations with Russian ambassador Sergey Kislyak. Flynn reportedly talked about sanctions relief for Russia before he officially took office. Flynn said he “inadvertently briefed” Pence with “incomplete information,” and later added he “crossed no lines.”

Still, critics say Flynn’s call is a crime under the Logan Act that was born amid one of America’s first foreign disputes.

In the late 1790s French revolutionaries began interfering with American merchant ships (upset that they hadn’t gotten adequate support from the U.S. for their cause). U.S. efforts to quell the brewing conflict between the two countries ended in failure, leading to a quasi-war at sea between the U.S. and France until 1800.

But in 1798, a private citizen from Philadelphia, Dr. George Logan, went to France to try to smooth over the tensions.

“In France he was hailed by the newspapers as an envoy of peace and was received by [French foreign minister] Talleyrand,” according to a paper filed with the Congressional Research Service. “The French Directory, having concluded that it was politically wise to relax tensions with the United States, issued a decree raising the embargo on American merchant ships and freed American ships and seamen.”

The reception back home was furious. Logan’s actions were pilloried by George Washington, and President John Adams urged Congress to outlaw such actions by private citizens.

In 1799 Congress passed the act and named it after Logan, but he wasn’t prosecuted. Four years later, a farmer was though.

Francis Flournoy wrote a letter from “A Western American” in Kentucky’s Guardian of Freedom paper in March 1803. The farmer said that President Thomas Jefferson’s administration and the East Coast elite didn’t understand the concerns of the West and people like him. Flournoy’s solution: That the land now known as the Louisiana Purchase secede, and ally itself with France and Spain.

Flournoy was indicted under the Logan Act 12 days later. He was charged with “unlawfully commencing a written correspondence, indirectly, with the government of the French nation… and with intent to influence the measures and conduct of the said government of the French nation towards the United States, and with an intent to defeat the measures of the government of the United States, relative to a certain controversy.”

Flournoy fled Kentucky, the Louisiana Purchase was completed, and the farmer never stood trial.

Since then, no one has been charged with violating the law, but could Flynn?

According to the act, a citizen who “without the authority of the United States, directly or indirectly commences or carries on any correspondence or intercourse with any foreign government or any officer thereof, in relation to any disputes or controversies with the United States, or to defeat the measures of the United States, shall be fined under this title or imprisoned not more than three years, or both.”

By the letter of the law, Flynn may have done just that by discussing U.S. sanctions against Russia with Ambassador Sergey Kislyak before he took office as Trump’s adviser.

But the act laid untouched for two centuries. Critics say the “content-based restriction” on free speech wouldn’t hold up in court these days, after 20th-century Supreme Court rulings bolstered the First Amendment.

And others say such a prosecution of Flynn, however unlikely, would violate the spirit of the law.

“[Flynn was] only in this position because, as of January 20, he [would] be exercising government authority,” University of Texas Law School professor Steve Vladeck argued on the website Just Security when questions about Flynn’s conversations first surfaced.

“And it seems to me that the spirit of the Logan Act would not extend to preventing the President-Elect (and his subordinates) from taking steps to enable the exercise of the authority to conduct foreign affairs that they will soon formally possess—and that the electorate has already chosen to bestow upon them.”