It is a crime for witnesses to lie in interviews with the special counsel, even when not conducted before a grand jury.

That leaves notably few top Trump aides left to speak. Vice President Pence has apparently not spoken with Mueller. Nor has Donald Trump Jr., nor, of course, has his father—yet.

For months, the conventional wisdom, especially after charges against Manafort and Gates and Papadopoulos’s guilty plea, was that Mueller was moving slowly and methodically, gradually working from the outside up in the manner of an organized-crime investigation, and that his path and timeline would remain opaque. Trump lawyer Ty Cobb has been ridiculed for repeatedly predicting a quick resolution to the special-counsel investigation—perhaps by Thanksgiving, then the end of 2017. Does the sudden onrush of interviews and news offer some vindication for Cobb, suggesting that while he may have been too fast, he was not wrong to predict a quick resolution?

The answer, of course, is, who knows? As I wrote in September, there’s a great temptation to conduct augury using what little is known about the special counsel’s probe, especially given the potential stakes and Mueller’s own silence. Yet experts agree that it’s very hard to make solid bets about his path. Similar, previous investigations—Watergate, Iran-Contra, Whitewater—all took much longer than Mueller has so far; he won’t hit the one-year mark until May.

What about the Trump interview? The president’s legal team will no doubt try to bargain for minimal exposure, and Cobb has expressed worry about Trump being led into a “perjury trap,” where he ends up lying under oath about (what Cobb would surely argue was) a minor matter. Trump’s attorneys might seek to prevent their client from having to testify more than once, especially since that would heighten the risk of a perjury trap.

John Q. Barrett, a professor of law at St. John’s and former member of the Iran-Contra independent counsel’s team, warned against reading too much into interviews with high-level officials.

“It’s not one and done,” he said. “Presumably with the president, you’re not going to do a lot of returns to him. But even theoretically with the president I can imagine an investigation having a first contact, but that might not be the one and only.” (Barrett also rejected the idea of a perjury trap: “Prosecutors do not do that. It’s unethical. It’s against Department of Justice policy.”)

Bill Clinton, for example, gave a deposition in January 1998, in which he perjured himself, and then in August of the same year appeared before a grand jury. If Mueller questions Trump mostly about obstruction, he could still seek to interview him later about collusion with Russia—which might be more likely only after the Manafort and Gates charges are resolved, and they can be called to testify. Trials aren’t expected to start in that case before September or October.