The media reports that Bob Mueller wants to question Donald Trump hardly sound like great news for the White House—but there could be a silver lining.

At the very least, the stories suggest that the special counsel is approaching the final stages of his Russia investigation. Prosecutors virtually never interview their highest-ranking potential target until they've compiled most of the evidence, because you want the most ammunition for that high-stakes encounter.

That would mean the prospect of the Mueller investigation dragging on for another year or two, casting a dark shadow over the White House, would be greatly diminished.

The news, first reported by NBC, was quickly confirmed elsewhere. The New York Times says that "Robert S. Mueller III told President Trump’s lawyers last month that he will probably seek to interview the president, setting off discussions among Mr. Trump's lawyers about the perils of such a move"—this according to "two people familiar with the discussion."

The Washington Post says Mueller has indicated his office "is likely to seek an interview with the president, triggering a discussion among his attorneys about how to avoid a sit-down encounter or set limits on such a session"—also according to two unnamed sources.

It was probably inevitable that Mueller wouldn't wrap things up without attempting to sit down with the president. Ken Starr took Bill Clinton's famous "the meaning of is" testimony in front of a grand jury, although this took place at the White House.

The Post says the "the president’s attorneys are reluctant to let him sit for open-ended, face-to-face questioning without clear parameters, according to two people familiar with the discussions. Since the December meeting, they have discussed whether the president could provide written answers to some of the questions from Mueller’s investigators, as President Ronald Reagan did during the Iran-contra investigation. They have also discussed the obligation of Mueller’s team to demonstrate that it could not obtain the information it seeks without interviewing the president."

This suggests that some delicate negotiations may soon be under way.

The Times quoted an unnamed source as saying that Mueller "appeared most interested in asking questions about the former national security adviser, Michael T. Flynn, and the firing of the F.B.I. director, James B. Comey — not the broader question of possible collusion with Russia. Those topics signal an interest in whether Mr. Trump tried to obstruct justice."

If that's accurate, it means the Russian collusion question—which the president has repeatedly attacked as fake and which is why the probe was launched in the first place—is fizzling. And that would represent a measure of vindication for the White House.

Obstruction, of course, is serious business; it was one of the charges in the House Judiciary Committee’s vote to impeach Richard Nixon. But this scenario would leave Mueller in the strange position of arguing that Trump or his associates were trying to cover up something that he can’t prove was a crime.

Paul Manafort's indictment mainly has to do with Ukraine. Flynn pleaded guilty to lying to the FBI about his contacts with Russians, but he also lied to the White House. The only plea that seems more directly connected to a collusion narrative is that of George Papadopoulos, but he was a low-level adviser.

It could be tricky for Trump to explain why he fired Comey, and respond to Comey's testimony that the president asked him to go easy on Flynn. But a president does have the legal authority to dismiss his FBI chief.

White House lawyers have been cooperating with the special counsel, and the president has dismissed media speculation that he might fire Mueller.

"We have been very open," Trump told reporters at Camp David. "We could have done it two ways. We could have been very closed, and it would have taken years. But you know, sort of like when you've done nothing wrong, let’s be open and get it over with."

If an interview with the president signals the final phase of this investigation, the strategy of cooperation could look smart in the end.

That is, unless Mueller is sitting on something explosive that miraculously has failed to leak.