In the meantime, the questions prepared by Mueller — combined with some nuggets buried in last week’s House Intelligence Committee report — offer some intriguing clues into the progress and direction of the special counsel’s probe. Here are a few of them.

1. Collusion is very much still on the table.

Much has already been made of Mueller’s proposed question to Trump: “What knowledge did you have of any outreach by your campaign, including by Paul Manafort, to Russia about potential assistance to the campaign?” The wording of the question suggests Mueller may well be aware of such “outreach,” presumably informed by the cooperation he has received from Manafort’s former deputy, Rick Gates. But other questions also point to other evidence Mueller has gathered on the collusion front. One of them appears to involve the months-long effort by Papadopoulos to broker a meeting during the campaign between Trump and Putin. Papadopoulos first floated the idea of such a summit directly to Trump at a March 31, 2016 meeting of the then candidate’s newly appointed foreign policy advisory board. Jeff Sessions has testified he quickly shot the idea down. But as David Corn and I first disclosed in our book, “Russian Roulette: The Inside Story of Putin’s War on America and the election of Donald Trump,” Papadopoulos has secretly told Mueller’s prosecutors that Trump gave him the green light to pursue the summit idea, telling him he found the idea “interesting” and then looked to Sessions to follow up.

2. Potential witness tampering is also under scrutiny. 

One of the more intriguing of Mueller’s proposed questions involve efforts by the president to communicate with his former national security advisor Flynn after he was fired for lying to Vice President Mike Pence about his contacts with Russian ambassador Sergey Kislyak.

Mueller wants to ask the president “what efforts were made to reach out to Mr. Flynn about seeking immunity or possible pardon?” This question was likely prompted by a New York Times report that Trump lawyer Dowd floated the idea of a pardon to Flynn’s lawyer. But there may well be more to Trump’s contacts with Flynn after he left the White House than that. Last May, Yahoo News reported that Flynn told friends that he had recently been in touch with the president who urged him to “stay strong” as the Russia investigation was closing in on him. Flynn, who pleaded guilty to lying to the FBI and is now cooperating with Mueller, would presumably know exactly what the president communicated to him. And what he communicated to the president, including during the campaign. One largely overlooked nugget buried in the House Intelligence Committee report released last week was that Flynn, the former Defense Intelligence Committee chief and his son met with Kislyak at the Russian ambassador’s residence in December 2015. That was shortly before Flynn flew off to Moscow to attend the 10th anniversary celebration of RT, the Russian government propaganda station, where he sat next to Putin at dinner. It was the first hint that Flynn had contact with Kislyak prior to Trump’s 2016 election.

3. Trump’s attempt to do business in Russia is on Mueller’s radar screen.

The questions that might be expected to rile the president the most include a couple relating to his attempts to build a Trump Tower in Moscow — the first hard sign that the special counsel is probing Trump’s business operations.

One of the questions involves his communications with Aras Agalarov, the billionaire Russian oligarch who partnered with Trump to stage the Miss Universe pageant in Moscow in 2013. Trump and Agalarov signed a “letter of intent” to build a Trump branded project in the Russian capital.

That deal collapsed after the Obama administration and the European Union imposed sanctions on Russian businesses following Putin’s 2014 annexation of Crimea and intervention in Ukraine. But Trump didn’t stop his efforts. Another Mueller question asks “what communications did you have with Michael D. Cohen [Trump’s longtime lawyer], Felix Sater [a former Trump real estate advisor] and others, including foreign nationals, about Russian real estate developments during the campaign?” This concerns a separate letter of intent to build a Trump Tower Moscow that was signed by Trump in October 2015 — while he was running for president. Trump’s real business partners in this deal were never clear. Russian tax records show that I.C. Expert Investment, the company with whom he signed the letter of intent, was owned by three murky offshore companies controlled by Cypriot lawyer deeply involved in Russian finance. When Sater initially pitched the project to the Trump Organization, he pitched it as a way to boost Trump’s run for president. “I will get Putin on this program and we will get Donald elected,” Sater wrote in an email to Cohen at the time. “Buddy our boy can become president of the USA and we can engineer it. I will get all of Putin’s team to buy in on this, I will manage this process.”

4. What did the president know about the Trump Tower meeting—and when did he know it?

The June 9, 2016 meeting at Trump Tower — during which top Trump campaign officials sat down with a delegation of Russians after being told they were about to receive “official” and “sensitive” documents about Hillary Clinton from Kremlin files — remains a major focus for Mueller. Of the questions on this topic, one leaps out: “When did you become aware of the Trump Tower meeting?” Trump and his son, Donald Trump Jr., have both said that Trump himself knew nothing about it at the time; Donald Jr. has said he only told his father much later in the summer of 2017, shortly before it was revealed by the New York Times. But Rep. Adam Schiff, the ranking Democrat on the House Intelligence Committee, last week revealed that the panel failed to pursue leads that he believed might show otherwise. Trump Jr.’s phone records show that after receiving an email from Rob Goldstone, a publicist, informing him that Aras Agalarov and his son, the pop singer Emin Agalarov, were arranging to have the supposedly anti-Hillary documents brought to Trump Tower, the president’s son made two attempts by phone to reach the younger Agalarov in Moscow. Between those calls, according to Schiff, was a phone call >>with< a request that was denied by the Republican majority — to determine if the recipient was the future president.  But Mueller is operating under no such constraints — another reason why the Russian investigation poses such potential dangers for Trump.