This element of Barr’s summary caused an immediate backlash from Democrats, including House Judiciary Committee Chairman Jerry Nadler, who tweeted that there should be full transparency over how Barr came to his decision and a thorough detailing of the evidence surrounding obstruction of justice.

Perhaps the biggest question surrounding Barr’s letter is what evidence the special counsel found that Trump was involved in obstruction of justice. Barr wrote that Mueller’s report essentially left it open as to whether Trump committed such a felony ― claiming Mueller presented evidence “on both sides of the question,” and “ultimately determined not to make a traditional prosecutorial judgment.” Barr and Deputy Attorney General Rod Rosenstein then took it on themselves to decide that Trump shouldn’t be charged.

But Barr’s summary, which was just four pages long, leaves open major questions about the Mueller investigation’s findings and already has many top Democrats demanding that the full report be released. Here are some of the biggest unanswered questions from Barr’s letter.

U.S. Attorney General William Barr released his summary of special counsel Robert Mueller ’s report into Russian interference in the 2016 presidential election on Sunday evening, detailing that in Barr’s view the president did not commit any crimes.

Barr says that the President may have acted to obstruct justice, but that for an obstruction conviction, “the government would need to proved beyond a reasonable doubt that a person, acting with corrupt intent, engaged in obstructive conduct”.

But Special Counsel Mueller clearly and explicitly is not exonerating the President, and we must hear from AG Barr about his decision making and see all the underlying evidence for the American people to know all the facts.

Adding to the Democrats’ pushback over Barr and Rosenstein’s decision is that they are both Trump appointees. Barr also wrote an unusual memo to Rod Rosenstein last year ― before his nomination for attorney general ― in which he heavily criticized the special counsel investigation and specifically singled out Mueller’s probe into potential obstruction of justice as a point of disagreement.

What Did Mueller Find About Collusion?

Although Barr’s letter says that the special counsel did not find evidence to establish a conspiracy charge, there have been continuous reports of meetings and communications between campaign officials and Russian officials or proxies. Even if these interactions did not reach the high bar necessary for a charge of criminal conspiracy, there are still major questions over how extensive these connections were and those involved.

Barr did include in his letter that there were “two main Russian efforts to influence the 2016 election,” which involved a disinformation campaign on social media and the hack of Hillary Clinton campaign chairman John Podesta’s emails. Those emails were then distributed to WikiLeaks and released to the public prior to the election.

But the full Mueller report likely gives more details about the Russian attempts to contact the Trump campaign, as well as the extent to which Trump associates such as Roger Stone were communicating with WikiLeaks and what Trump knew about such interactions. It may also reveal more about incidents such as Donald Trump Jr.’s secret meeting with a Kremlin-connected Russian lawyer in 2016 at Trump Tower in Manhattan.

What Happened With Jerome Corsi?

One of the minor figures in the Mueller investigation was conspiracy theorist Jerome Corsi. The special counsel offered Corsi a plea deal last year that would have required him to plead guilty to lying to investigators and obstructing justice. Corsi rejected the deal, and ultimately was never charged with any crimes.

It remains unclear what was behind this episode and why Mueller was unable or unwilling to charge Corsi, something that the full report may explain. Corsi was reportedly looked at as a potential middleman between Roger Stone and WikiLeaks.

What Is The Mystery Supreme Court Case?

Another unanswered question in the Mueller investigation concerns a secretive legal battle involving an unnamed foreign-owned corporation that the special counsel’s office subpoenaed during its probe. The business ― known in court filings only as “Corporation” ― tried to fight the subpoena in a legal challenge that reached the Supreme Court. Ultimately, the Supreme Court decided not to hear the case and left a lower court ruling in place that forced the business to comply with the subpoena.

But it’s still unclear what Mueller’s interest in this corporation was, why the Supreme Court made the decision and even what country the business is from. It remains one of the enduring secrets of the investigation.

Will We Get To See The Full Report?

There has been a long-standing push from Democrats to demand that the full Mueller report be released, and the questions over the obstruction of justice decision have only intensified the demand. Both Republicans and Democrats have previously called for the report to be made public, and House Democrats could also potentially try to subpoena the report if Barr refuses to release it.

Barr wrote in his letter that he would attempt to make as much of the report public as he can, but stopped short of saying he would release it in full.