Perspective: It’s not up to President Donald Trump whether he testifies in the special counsel’s investigation.

As we have discussed from time to time, the story line that President Donald Trump has the option whether to sit down with special counsel Robert S. Mueller III is simply wrong. Mueller has the option to ask the grand jury to issue a subpoena to compel Trump’s testimony under oath and without his lawyer present. (Witnesses can go outside to consult with a lawyer, but witnesses ordinarily do not get to bring their attorney into the grand jury room.) Perhaps now Trump, his lawyers and the TV talking heads will approach Trump’s testimony more realistically: It isn’t up to him to decide to cooperate — unless he wants to take the unprecedented step of thwarting an investigation into his own wrongdoing by invoking the Fifth Amendment.

The Post reports:

“In a tense meeting in early March with the special counsel, President Trump’s lawyers insisted he had no obligation to talk with federal investigators probing Russia’s interference in the 2016 presidential campaign. But special counsel Robert S. Mueller III responded that he had another option if Trump declined: He could issue a subpoena for the president to appear before a grand jury, according to four people familiar with the encounter.”

While this is the first confirmation of such a warning, I have no doubt that Trump’s lawyers have been aware of Mueller’s ability to get a subpoena. If they have hidden that uncomfortable truth from Trump, they will have some explaining to do.

The Post’s report also suggests that a list of questions came from Trump’s side. (“Trump lawyer Jay Sekulow compiled a list of 49 questions that the team believed the president would be asked.”)

Why would Trump’s team leak the questions? It seems that Trump’s lawyers thought the list would show that Mueller was being overbearing or ranging too far. (“The president and several advisers now plan to point to the list as evidence that Mueller has strayed beyond his mandate and is overreaching, they said . .... ‘Mueller is in Kenny Starr territory now,’ said another Trump adviser, referring to how the controversial independent counsel investigation of Bill and Hillary Clinton’s real estate deals in Arkansas ended up examining the president’s lies about his sexual relationship with a White House intern.”) The fact remains that Starr was empowered, as Mueller is now, to investigate crimes revealed in the course of the investigation.

If members of Trump’s team thought they’d show that Mueller really was on a witch hunt, they blew it. The list of questions establishes concrete lines of inquiry appropriate to determining whether obstruction of justice and/or improper coordination with Russia occurred. This is not a free-ranging inquiry into Trump’s business deals.

Alternatively, Trump’s team might have let the list out to shake up their own client, impressing upon him the seriousness of the inquiry and the need to delay as long as possible a Q&A with Mueller.

Whatever their mind-set, members of Trump’s team surely know three critical facts: Mueller is operating within the jurisdiction granted to him; the ability to investigate and indict for obstruction (or perjury or witness tampering) is inherent in any prosecutor’s mandate (otherwise people would block the investigation); and the Supreme Court in the Nixon case held that the president must comply with a subpoena seeking evidence in criminal matters.

Now in this case, the primary purpose of the testimony might very well be to establish Trump’s own liability. Even if one accepts that a sitting president cannot be indicted, the testimony could be used to prosecute after Trump leaves office and, of course, could be packaged up for Congress to use in impeachment proceedings.

If we get to the point where Trump’s testimony is compelled and he must consider invoking the Fifth Amendment, it is fair to say his presidency will be over. The appearance, fair or not, that he is concealing wrongdoing by taking the Fifth will be hard to shake. Furthermore, invoking the Fifth, which is his personal right, makes clear that he can no longer uphold his office, which is to “take care” that the laws are faithfully executed. A Democratic-led House (a strong likelihood) then would feel compelled to move toward impeachment. (Even Republicans might agree — or plead with Trump to resign.)

But we are getting ahead of ourselves. For now, the proper framing is this: Trump can testify the easy way (not under oath, with his lawyer) or the hard way (alone in front of a grand jury). It’s nearly inconceivable that Mueller would relieve him of that dilemma. The prosecutor’s obligation is to find the truth, from all available sources. Mueller isn’t going to give Trump a pass.