If there were any doubts that Robert Mueller's investigation must go forward without harassment or interference, they were swept aside by the extraordinary events that took place in two courtrooms last week.

Paul Manafort was found guilty in Virginia by a jury of his peers on eight felony counts of bank fraud and tax fraud. Michael Cohen pleaded guilty in New York to eight felony counts of tax evasion, bank fraud and, most ominously for President Donald Trump, campaign-finance violations. These were not bit players whose eagerness and naiveté led them to commit indiscretions. Manafort is Trump's former campaign chairman. Cohen was Trump's personal lawyer and fixer, and one of his closest confidants.

The two resolutions continue Mueller's track record of success since he was chosen to take over the probe into Russian election interference and related matters in May 2017. They make clear that justice is being served, slowly but surely. And they provide yet more evidence, if any really was needed, that Mueller's critics — and that includes Trump and other elected leaders in Congress — need to back off and let him finish his work.

The list of those who have pleaded guilty to various charges includes Trump's former national security adviser Michael Flynn, former campaign adviser George Papadopoulos, Manafort's business partner Rick Gates and Dutch attorney Alex van der Zwaan. Mueller also indicted, backed by an incredible level of detail, 25 Russian citizens and three Russian entities involved in election interference and hacking.

Mueller's prosecutors secured Manafort's conviction, and are scheduled to try him in Washington on other charges in September. Mueller determined that evidence he uncovered on Cohen was outside the scope of his mandate and referred the matter to U.S. attorneys in the Southern District of New York, who negotiated Cohen's plea deal. Cohen admitted he paid two women to stay quiet about their alleged affairs with Trump, that he made the payments "in coordination and at the direction of a candidate for federal office," and that he had done so "for the principal purpose of influencing the election" for president in 2016.

And with that, one of the threads of this many-faceted investigation entered the White House.

Trump says he is upset because some of the charges have nothing to do with Russian election interference. But Mueller's mandate includes following up on any evidence of criminal conduct he uncovers. This is utterly typical of these kinds of investigations. And Mueller has kept his head down, has resisted the urge to respond to personal provocations and has moved steadily forward.

There is no witch hunt, contrary to Trump's claims. Nor is Mueller disgraced or discredited. Now it's time to let him complete the investigation.

FROM AN EDITORIAL IN NEWSDAY