One ironic outcropping of the Russia-meddling probe is that it took a special investigation of the Republican president's "America First" campaign to prompt a crackdown on purportedly unregistered foreign agents.
On Friday, it was revealed that Sam Patten, a former associate of ex-Donald Trump campaign chairman Paul Manafort, pleaded guilty to failing to register in the U.S. as a foreign agent for his lobbying on behalf of a pro-Russia Ukrainan political party.
Patten has been a business partner of the indicted Konstantin Kilimnik, a Russian who was indicted in absentia for obstruction along with Manafort. Special counsel Robert Mueller's office referred the case to the U.S. attorney for the District of Columbia.
Mueller has been using the Foreign Agents Registration Act as a tool. By most accounts it has been the subject of little criminal enforcement over the years. But last month the references for possible prosecution to different federal offices became a noticeable cluster.
"Mueller has referred matters to the Southern District of New York involving longtime Democratic lobbyist Tony Podesta and his work for his former firm, the Podesta Group, and former Minnesota Republican Rep. Vin Weber and his work for Mercury Public Affairs, the sources said.
"One source said that former Obama White House counsel Greg Craig, a former partner at law firm Skadden, Arps, Slate, Meagher & Flom LLP, is also part of the inquiry.
"None of the entities involved have been charged with wrongdoing, and there is no indication the SDNY inquiry will result in criminal charges."
The conservative Weekly Standard highlighted the previous rarity of such cases:
"To say that FARA was, at least until recently, an obscurity would be a wild understatement. In 2016, the Justice Department’s inspector general audited the enforcement of FARA and 'found that historically there have been hardly any FARA prosecutions.' "
Last year it also drew wide notice that former top Trump national-security adviser Michael Flynn — who pleaded guilty to lying to the FBI about his contacts with Russian Ambassador Sergey Kislyak — registered retroactively as a foreign agent for work involving Turkey.
Federal officials also have turned to another relatively unusual source of prosecution — campaign finance laws. Former Trump fixer-lawyer Michael Cohen pleaded guilty to violating them, implicating Trump.
But it is the FARA cases that reportedly have lobbyists in the undrained Washington swamp taking extra care these days to make sure they comply.