Special Counsel Robert Mueller's 12-point indictment of former Trump campaign manager Paul Manafort and Trump campaign official Rick Gates is the first significant development in the case in the investigation of alleged collusion with Russia as that country's government meddled in the 2016 U.S. presidential election.
In the process, Mr. Mueller has also disclosed that a former Trump campaign figure, George Papadopoulos, has already pleaded guilty to lying to the FBI in the matter, suggesting a plausible leak in the Trump dike of deniability.
The Trump administration has tried to brush off both developments by saying Mr. Manafort's alleged offenses occurred before he had joined the campaign and had nothing to do with Mr. Trump, and that Mr. Papadopolous was a brief volunteer, free of any culpability.
The president has seized both arguments to support his contention that the whole investigation is a "hoax" and "fake news" sustained by a hostile press. Not only that, he says, if there has been any collusion with the Russians, it was by the campaign of "Crooked Hillary" Clinton.
He has tried to convince reports that her campaign in 2016 first funded the "opposition research" against him by a for-hire professional organization, thus turning the investigation on its head. Mr. Trump argues now that Mr. Mueller should be targeting her campaign, not his.
But the diversion isn't likely to deter Mr. Mueller's team of veteran sleuths and prosecutors, which has methodically assembled a mountain of documents establishing the basis for the conviction of Mr. Papadopoulos and the indictment of Messrs. Manafort and Gates.
The two legal actions are part of Mr. Mueller's strategy to painstakingly build the cases against the indictees, and then to squeeze them for more damaging information against Mr. Trump, the obvious big fish in the pond of alleged corruption that ultimately could lead to the president's removal from office.
That objective, through impeachment or some other legal course, remains far from likely at this juncture — that is, unless Mr. Trump's behavior can be successfully couched as abuse of presidential power in the undefined constitutional rubric of high crimes and misdemeanors.
The White House defense of "Nothing to see here," obediently mouthed by press secretary Sarah Huckabee Sanders, has assured another round of verbal sparring between her and the press corps that daily covers the president. Mr. Trump himself daily fuels it with tweets arguing if there is any collusion with the Russians, Hillary Clinton has been the all-purpose colluder.
If there is any obvious takeaway from this first tipping of Mr. Mueller's hand, it's that the veteran and highly respected federal prosecutor is engaged in a long-term and meticulous quest that Mr. Trump can short-circuit only at the risk of further imperiling his own case. He and his legal advisers have repeatedly said he has no intention of firing Mr. Mueller, an action that would only hand the investigating sleuths prima facie grounds for charging abuse of presidential power.
There's a pointed irony in all this. Had Mr. Trump's handpicked Attorney General Jeff Sessions not recused himself from the inquiry into Russian election meddling, Mr. Mueller likely never would have been appointed special counsel in the investigation.
Mr. Sessions stepped aside because he had been a major figure in the Trump presidential campaign, to Mr. Trump's later outspoken chagrin. Deputy Attorney General Rod Rosenstein, a career prosecutor, then made the Mueller appointment.
Mr. Mueller's solid reputation as a relentless truth-seeker is at stake now as he takes on perhaps the toughest challenge to that reputation in his long career as a defender of the American judicial system. He isn't likely to blink or back off how as the investigative process appears now to be closing in on the president.
The latest public-opinion polls indicate Mr. Trump's base of support among voters may be shrinking, but that he retains a hard core of backing within the Republican Party, in Congress and in the country.
They don't have a vote in the ongoing legal process. So Mr. Mueller is on perhaps the only feasible track available eventually to pry loose Mr. Trump's grip on presidential power that has this country, and many beyond as well, in a state of uncertainty and consternation.
Jules Witcover is a syndicated columnist and former long-time writer for The Baltimore Sun. His latest book is "The American Vice Presidency: From Irrelevance to Power" (Smithsonian Books). His email is firstname.lastname@example.org.