The Foreign Agents Registration Act dates back to 1938 and stemmed from fears about covert Nazi propagandists who were active in the United States during the run-up to World War II.

The case of Paul Manafort, who is being indicted on 12 counts among them being an unregistered agent of a foreign principal and making false and misleading FARA statements, might eventually go down as one of the best-known consequences of FARA, a relatively vague statute that usually amounts to little more than an honor system despite its tough-sounding, spy-catching criminal penalties.

The law requires lobbyists, lawyers, public relations and advertising executives to disclose their representation of foreign governments and foreign political parties. They are supposed to detail the scope of their work and to disclose their contacts with U.S. government officials, including members of Congress.

The Justice Department has pursued only seven criminal prosecutions in the past 50 years, according to a report last year from the DOJ’s inspector general.

Robert Kelner, an expert on lobbying laws including FARA, represents Michael Flynn, President Donald Trump’s former national security adviser and another prominent person in the Mueller probe. He said more than a year ago that FARA prosecutions on their own were rare. 

“In virtually every reported FARA case, there’s something more serious going on — usually espionage, terrorism, trade sanctions busting or bribery,” Kelner told CQ magazine in September 2016.