Special Counsel Mueller is slowly closing in on Trump.

The truth and the president haven’t always gotten along. Actually, quite the contrary. Among the occupants of the White House, there are many examples of lying by Richard Nixon and Bill Clinton, both of whom were threatened with impeachment. George H.W. Bush was destroyed by an unfulfilled promise: “Read my lips, no new taxes.” For his son, it was the lie about weapons of mass destruction that caused him to invade Iraq.

The contribution from the current president is unparalleled. Trump and the truth are incompatible. He lies more than he blinks, as says the saying goes, hence the danger of a lengthy interrogation over Russian interference in the presidential campaign, which Special Counsel Robert Mueller intends to subject Trump to. His lawyers know that the more questions he is asked, the more likely it is that he will get caught up in a lie.

Lawyers are interested in knowing the intentions of the special counsel, who has released 49 question topics that are most dangerous for somebody who finds it difficult to draw a clear line between reality and his fantasies. The underlying theme of the questions involves three characters and a common theme among them, Russian interference in the 2016 election. The characters are his first and short-lived national security advisor, Michael Flynn, dismissed for lying about his contact with the Russians. The second is the attorney general, who also had contact with the Russians and offered his resignation so as to avoid being forced to quit; and the final subject is the former director of the FBI, James Comey, who was investigating them and was dismissed by the president.

For the first time, these 49 questions offer an idea of the breadth of the investigation into the collusion between the Trump campaign and the interests of Moscow, as well as the efforts to shield it all from the Oval Office. None of the questions can be answered with just one word; they require explanations, which could easily trip up a character so prone to distortion and self-indulgence. Their purpose is clear: to find out whether there has been obstruction of justice by the president, an issue which drove Nixon and Clinton to the brink of impeachment.

The biggest irony of the questionnaire, which The New York Times gained access to from an unknown source, is that it was drafted by one of Trump’s lawyers after meeting with the special counsel's investigators. The lawyer, pursuant to Trump’s wishes, wanted to know the extent of Mueller’s interests in order to deter Trump from agreeing to the interrogation, given the lawyer’s being inexplicably sure of Trump’s innocence and persuasive ability.

Mueller has alleged no charges against Trump, at least for the time being, but he has already shown his intention of interrogating Trump by issuing, if necessary, a subpoena for him to appear before a grand jury. This is something that presidential lawyers try to avoid at all costs, and this could end up before the Supreme Court. With impeachment on the horizon, these 49 questions will hover indefinitely above Trump’s presidency for as long as they don’t receive satisfactory answers.