While the Manafort-Gates indictments suggest diving into the underside of lobbying, the electoral tampering charges directed at the Russian troll farms and hackers suggest newer and even more pressing priorities. Mr. Mueller’s indictments were limited to Russian efforts to influence the 2016 presidential election. But the United States has plenty of domestic trolls and malicious hackers, too. Some of them threaten journalists; others have already used millions of stolen identities to attack federal agencies with fake opinions. To say this is an area of national vulnerability is a gross understatement.

There is far more to the agenda suggested by the Mueller probe than just putting some bad guys in jail. What the indicted targets threatened were key pillars of democracy itself, including an uncorrupted electoral process, a government free from secret foreign influence and the credibility of the main channels of speech. It is the constitutional duty of law enforcement to protect the basic institutions of democracy, but other priorities have taken precedence.

Such as the so-called war on drugs. Since the 1970s, when President Richard Nixon announced it, federal and state law enforcement has been asked to put much of their time and resources into fighting drug crimes, at the expense of other offenses. The result is well known to anyone who has worked in the court system or law enforcement itself. Violations of election law are rarely detected and even more rarely prosecuted. For the rich and immoral, it seems foolish not to try tax avoidance. The hard truth is that crimes committed by people like Mr. Manafort have become crimes that pay, for the chances of being caught are low, and if you are caught, the sentences are relatively light. In fact, federal corruption and white-collar prosecutions are at a 20-year low and down 40 percent since 1998, according to tracking by Syracuse University.

There is a grave danger that the swirling politics of the Mueller report will lead us to forget what it revealed: a toxic cloud of routine criminality surrounding the American political system. It echoed previous efforts, like the F.B.I.’s Abscam sting in the late 1970s, which yielded the corruption convictions of one senator and six congressmen, not to mention the more recent corruption trials in New York, Illinois and California.

This is why we need political leaders who will free up investigators and prosecutors who have been fighting the war on drugs and put them to work investigating Manafort-style foreign corruption, Cohen-style financial crimes and Russian-style election propagandizing. The Mueller inquiry may be over, but it should inspire the work of a new generation of prosecutors who want to fight one of the great evils of our time.

Tim Wu (@superwuster) is a law professor at Columbia, a contributing opinion writer and the author, most recently, of “The Curse of Bigness: Antitrust in the New Gilded Age.”

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