Its main conclusion is a very good one for President Donald Trump: Mueller found that neither Trump nor anyone in his campaign conspired or coordinated with the Russian government to help him win the election, according to Attorney General Bill Barr's assessment of the Mueller report.

Barr's conclusion that not enough evidence existed to charge Trump with obstruction of justice in the investigation is less fulsome, as Mueller noted that his findings "do not exonerate" Trump fully on that question.

In short: We know a hell of a lot more about what Mueller found -- and what it all means for Trump and the country -- than we did a week ago. Or even three days ago, when Barr acknowledged that Mueller had finished his investigation and submitted it. But there are also a number of questions that remain -- about the actual Mueller report, about why so many people in Trump's orbit lied about their interactions with the Russians and whether we will ever actually hear from Mueller.

In each episode of his weekly YouTube show, Chris Cillizza will delve a little deeper into the surreal world of politics. Click to subscribe!

Below, the nine most pressing unanswered questions.

Why didn't Mueller talk to Trump in person?

For months (and months) Trump and his legal team hemmed and hawed about whether the President would sit down with Mueller and answer questions. "I would love to speak. I would love to. Nobody wants to speak more than me," Trump said in May 2018 , before adding that his legal team had advised him against sitting down for an interview with Mueller's team. Trump lawyer Rudy Giuliani's entire job on the legal team seemed, at times, to be focused on negotiating with Mueller about whether Trump would agree to an in-person sit-down. Ultimately, in November 2018, Trump submitted written answers to questions from Mueller -- and limited his responses to questions regarding any collusion during the 2016 presidential campaign, insisting that questions tied to either the transition or his presidency were protected by executive privilege.

"It has been our position from the outset that much of what has been asked raised serious constitutional issues and was beyond the scope of a legitimate inquiry," Giuliani told CNN in a statement at the time . "This remains our position today. The President has nonetheless provided unprecedented cooperation. The special counsel has been provided with more than 30 witnesses, 1.4 million pages of material, and now the President's written responses to questions. It is time to bring this inquiry to a conclusion."

A source told CNN that the special counsel's office deliberated at length with DOJ officials about issuing a subpoena for Trump to be interviewed, but ultimately a decision was made to move forward without it.

The question we still don't know the answer to is whether Mueller was fully satisfied with Trump's written answers or whether he would have liked to follow up with an in-person conversation. And, if the latter is true, did Mueller simply not believe that Barr and/or Deputy Attorney General Rod Rosenstein would have signed off on it?

Will we ever see Trump's written answers?

For all of Trump's bluster about the Mueller probe -- "NO COLLUSION" ad infinitum -- the only time he ever answered questions under the penalty of perjury was when he responded in writing to Mueller's questions. Which makes those written responses potentially very, very interesting. Asked about the possibility of releasing Trump's written answers, Trump attorney Jay Sekulow told CNN's Alisyn Camerota on Monday that he would oppose such a move. "Well, that would not be a position that I would want, to just make a statement where we would release confidential communications that took place between the President of the United States and the Department of Justice or the special counsel's office," said Sekulow. "As a lawyer, you don't waive privileges and you don't waive investigative detail absent either a court order or an agreement between the parties. And you'd have to weigh a lot of factors there on how that affects other presidencies."

Will we ever see the full Mueller report?

Remember that what we know about Mueller's 22-month investigation comes from a four-page summary letter of the findings that Barr sent to Capitol Hill on Sunday. Outside of Barr and, presumably, a few others who helped him review Mueller's findings, no one has seen the full report (other than Mueller and his team, of course.) In that letter, Barr, as he did in his confirmation hearing for AG, insisted he would do his best to be transparent with the public. "I am mindful of the public interest in this matter," he wrote. "For that reason, my goal and intent is to release as much of the Special Counsel's report as I can consistent with applicable law, regulations, and Departmental policies."

It's the second part of that quote that leaves lots of room for interpretation. As Barr makes clear later in the letter, he believes there are parts of the Mueller report that cannot, by law, be released. He also added that he still "must identify any information that could impact other ongoing matters, including those that the Special Counsel has referred to other offices."

Given all of that, it is unlikely that the public will ever see the full Mueller report. The question is how much does Barr hold back -- and why. For his part, Trump said Monday afternoon that the release of the full Mueller report "wouldn't bother me at all."

Why did Mueller punt on obstruction, leaving the decision to Barr?

In Mueller's report, he wrote the following on the question of whether Trump obstructed the probe into Russian interference: "While this report does not conclude that the President committed a crime, it also does not exonerate him." By choosing not to offer any definitive conclusion on whether Trump obstructed justice, Mueller knew he was leaving the question to Barr who, as a private citizen in 2018, had written a memo in which he made the case that Trump had not, in fact, obstructed justice when it came to the firing of former FBI Director James Comey. Wrote Barr:

"Mueller should not be able to demand that the President submit to an interrogation about alleged obstruction. If embraced by the Department, this theory would have potentially disastrous implications, not just for the Presidency, but for the Executive branch as a whole and the Department in particular."

During his confirmation hearing, Barr sought to downplay the import of the memo -- insisting that, at the time, he was a private citizen without access to the full facts of the case, and that his point was a narrow, legal one. Still, Mueller had to know that in leaving the decision regarding obstruction to Barr that it was very likely that the AG would choose to not pursue it.

(One possible explanation as to why Mueller did what he did is that he simply didn't have proof beyond a reasonable doubt and, mindful that he was dealing with the President of the United States, simply didn't want to push the envelope -- leaving that decision to the highest law enforcement official in the country.)

Why did Barr choose to include and directly quote Mueller on the "does not exonerate" line on obstruction?

This one is complicated. Barr, a Trump appointee, is well aware that he is regarded by many Democrats as a Trump protector -- someone the President put in the job to ensure that nothing tied to the Mueller probe ever got to the Oval Office. Barr also knows that he, by the special counsel statute, is the gatekeeper of all the information gathered by Mueller over the 22-month investigation and, as such, is going to be heavily scrutinized for what he authorizes to be release and, more importantly, what he doesn't.

And so Barr wants to send a very clear signal that he isn't tipping the scales when it come to what he included in his summary of the Mueller report. So, yes, the big headline is that Mueller did not establish that there was coordination or collusion between the Trump campaign and the Russian government. But Barr also directly quotes from Mueller when it comes to the question of obstruction -- insulating himself from charges that he is shielding Trump from tough conclusions by the special counsel.

Did Mueller uncover any evidence of collusion?

Trump and his administration immediately seized on Barr's summation of the Mueller report by insisting his oft-repeated claims of "NO COLLUSION" had been proven. And he's likely right! But that's not exactly what Barr said. Barr quoted from the report saying "[T]he investigation did not establish that members of the Trump campaign conspired or coordinated with the Russian government in its election interference activities."

There is a difference between some strands of evidence that might suggest collusion and the ability to establish collusion beyond a reasonable doubt. In fact, there's a relatively wide chasm between those two things. So, did anything Mueller turned up fall into that gap? If so, what?

Why, if there was no collusion, were there SO many contacts between the Russians and Trump campaign. And why did so many of them lie about it?

This is the question that confounds me most in the wake of Barr's summation of the Mueller report. We know that at least 16 Trump associates had contact with Russians either during the 2016 campaign or in the presidential transition process. And we know that at least three of them -- national security adviser Michael Flynn, Trump fixer/lawyer Michael Cohen and foreign policy adviser George Papadopoulos -- lied to either Congress or federal investigators about those interactions. And in each case, those lies led to criminal charges.

If they didn't lie to protect a broader collusion effort, why did they lie? Perhaps to keep investigators away from other crimes unrelated to Russia's interference efforts in the 2016 campaign -- Trump campaign chairman Paul Manafort ended up being convicted with financial crimes related to his dealings with the Ukrainian government, for example.

Or maybe the people Trump attracted (and attracts) were simply as comfortable lying as telling the truth. Despite Trump's repeated assertions, his campaign (and his administration) was not exactly comprised of the best and brightest minds in the political and legal worlds.

Will we ever hear from Mueller himself about the report?

In the days leading up to the close of Mueller's investigations, people like House Intelligence Committee Chairman Adam Schiff (D-Calif.) and Judiciary Committee Chair Jerry Nadler (D-N.Y.) suggested they could well call Mueller to testify about his findings. Following the release of the report, Nadler, at least, shifted his attention to Barr. "In light of the very concerning discrepancies and final decision making at the Justice Department following the Special Counsel report, where Mueller did not exonerate the President, we will be calling Attorney General Barr in to testify before @HouseJudiciary in the near future," Nadler tweeted Sunday night . (It remains to be seen if Barr would agree to do so.)

If attention on Capitol Hill turns back to the idea of Mueller testifying, it's not clear that it would happen or, if it did, whether it would be revelatory. According to the special counsel statute which Mueller operated under, decisions about what to disclose in terms of his investigation are entirely in the hands of Barr and Rosenstein. So Mueller would be severely constrained about what he could say without the say-so of his two bosses. And, as WaPo's Aaron Blake points out , Mueller would be similarly limited in discussing information obtained via grand jury or details that did not lead to a prosecution. And, since Trump wasn't prosecuted, Mueller could be limited from speaking about what his investigation turned up on the President.

How much of the Steele dossier was confirmed by Mueller? And which parts?

We know, because of congressional testimony by Comey and others, that the Justice Department had confirmed some elements of the dossier put together by former British spy Christopher Steele. (Fusion GPS's opposition research efforts were originally paid for by a conservative news outlet, but later funded by Hillary Clinton's campaign and the Democratic National Committee.) But what parts of the dossier the Justice Department confirmed to be true we've never known. Did Mueller's findings confirm parts of Steele's dossier that the original FBi investigation hadn't? Again, if so, what parts?

While the Steele dossier has turned into a political football -- and the most salacious parts of it have never been confirmed -- it remains one of the seminal documents of this investigation. So, how true is it?

How useful was the cooperation of former Trump associates like Flynn, Gates and Cohen to the Mueller investigation?

The special counsel's office and the Southern District of New York cut plea deals with each of these men -- and more -- in order, we believed, to use information they and they alone possessed to catch larger fish in the operation. But now the Mueller investigation is over and none of those presumed "bigger fish" -- Trump, Donald Trump Jr., Jared Kushner -- have been charged or will be charged.