The Trump-Russia Investigation has accelerated. Armed with more evidence, and assisted by many of the most talented prosecutors and investigators in the country, special counsel Robert Mueller has impaneled a federal grand jury in Washington, D.C., to investigate whether President Trump and his associates colluded with Russian operatives to win the White House.

The fact that a federal grand jury has been impaneled is a significant development by itself; prosecutors don’t ordinarily convene grand juries unless there is a compelling reason to do so. The grand jury probe has expanded to include whether Trump obstructed justice by firing FBI Director James Comey. And it is also reasonable to believe that Mueller’s team is presenting evidence to the grand jury relating to financial connections between Trump, the Trump Organization, and Trump’s business associates with Russia and Russian interests.

We have a fairly good picture of where the grand jury investigation will go. Although it is not known who all has been subpoenaed to appear before the grand jury, many of them have already made statements, and we can reasonably assume that many of them already have been interrogated by federal investigators. We do not know whether any of these individuals has sought immunity from prosecution, been granted immunity, and has given testimony. Also, the fact that investigators obtained a search warrant to search Paul Manafort’s home in July is quite significant. Manafort was Trump’s campaign manager and had the most far-reaching financial ties with the Ukraine and Russia. Prosecutors in order to obtain a warrant must demonstrate probable cause to believe that Manafort committed federal crimes.

But clearly the most critical witness of all, and a likely target of the investigation, is Trump himself. As the grand jury investigation accelerates, and it focuses on Trump’s role, he will almost certainly be subpoenaed, and his testimony demanded. When that happens, what follows is unclear. Given Trump’s almost pathological contempt for the rule of law and for Mueller’s investigation, which Trump has repeatedly disparaged as a “witch hunt,” it is reasonably predictable that Trump’s lawyers will flout the grand jury’s investigation, mock Mueller, and refuse to testify. Will Trump succeed in spurning the process?

It should be emphasized that Trump has no legal privilege to avoid testifying before the grand jury. A grand jury, the most formidable investigative body in the United States, has the power to compel testimony from anyone, even a president, as Bill Clinton was compelled to do for the first time in U.S. history in the 1998 investigation by independent counsel Kenneth Starr into whether he lied about having an inappropriate relationship with White House intern Monica Lewinsky. And the Supreme Court has consistently reaffirmed the awesome powers of the grand jury, stating that “the public has a right to every man’s evidence,” including the president.

Although Trump’s lawyers most likely will advise him to resist testifying, probably claiming, as did former President Richard Nixon, some type of executive privilege, they will almost certainly lose. The Supreme Court decisively rejected that claim when Nixon refused to comply with a grand jury subpoena for records of conversations with White House associates.

When Trump is summoned, and presumably despite his resistance if ordered by a court to testify, will he comply? If not, will he be held in contempt? If Trump and the prosecutors try to negotiate some compromise, it is conceivable that the prosecutors will grant him immunity and thereby compel him to testify. As long as the prosecutors are careful, giving Trump immunity will not necessarily have any significant legal impact on the investigation, or the ability of prosecutors to charge Trump with crimes.

Immunity prevents the prosecutors from using Trump’s testimony against him, and from using any evidentiary leads gained from his testimony. But assuming that proof of Trump’s criminal offenses has already been discovered—such as proof of his obstruction of justice in seeking to halt the Flynn investigation or firing Comey—then despite giving him immunity, that proof can legally be used to prosecute him. And despite immunity, Trump can be prosecuted for perjury for giving false testimony.

Based on information that already is known, and reasonable inferences from other information that has likely been discovered (such as Trump’s financial records and testimony from other witnesses), these are some of the general areas that Trump likely would be questioned about. It is important to note that each of these areas is a relatively core subject, and would likely be the foundation to develop peripheral questions:

- Did Trump know when he was running for president and hired Paul Manafort as his campaign manager that Manafort had extensive financial dealings and lobbying work with Ukrainian and pro-Russian officials? Did he discuss Manafort’s connections with anyone?

- What was the basis for Trump’s decision to fire Comey? With whom did he discuss the firing? Did he discuss the firing with Attorney General Jeff Sessions?

- Did Trump know that his son Donald Jr., son-in-law Jared Kushner, and Paul Manfort met with a Russian lawyer during the campaign and allegedly obtained damaging information about Hillary Clinton? When did he learn about the meeting? From whom? What was his response?

- Did Trump alter Don Jr.’s initial statement about the Russia meeting, in which Don Jr. stated that he met to discuss Russian adoption but then changed this fabricated story to a new explanation that he wanted to judge Clinton’s “fitness.”

- Did Trump know that during his campaign his company was seeking to develop a real estate project in Moscow? What was he told? By whom?

- Did Trump have any financial dealings, projects, loans, and any other financial or other interests with Russia, Russian officials, and Russian business interests?

- Did Trump know of any contacts between persons involved in his campaign and Russian intelligence operatives? Who were these persons? Did he have any conversations with them?

As with so many other grand jury investigations, it is possible that the substantive offenses that the grand jury is investigating—here the principal focus is collusion between the Trump team and Russian officials to undermine the presidential election—may not be able to be proved conclusively. Nevertheless, when confronted with specific questions about their knowledge of certain facts, their previous statements, previous meetings, and numerous other relevant albeit peripheral details about subjects that reasonably should be memorable to the witness, it is not uncommon for the witness either to claim lack of memory, or lie.

And if Trump becomes a grand jury witness, and given his abundantly documented penchant for lying, brazenly, and almost reflexively, it is very likely that the prosecutors will be able to pose clear, specific, and non-ambiguous questions to Trump of which he might claim an inability to remember, but which he also might answer falsely and thereby commit a felony. Indeed, that is exactly how Independent Counsel Starr was able to lay the foundation for the impeachment of President Clinton by in effect trapping Clinton into lying about his conduct with intern Lewinsky.

Whether Trump will be indicted, for what, and the legal consequences, are not clear or predictable. Indeed, the question of whether a sitting president can be prosecuted at all has been hotly debated. Whether Trump is able to claim some type of presidential immunity from prosecution may ultimately have to be ruled on by the Supreme Court, as was the case with Nixon. The court did hold in the Paula Jones civil lawsuit that Clinton enjoyed no immunity from civil liability for unofficial acts committed before he became president. The lesson in that case is that no person is above the law, even a president. Whether that lesson applies to Trump may likely be decided soon.