Barr’s report could very well end up being blank, which itself would be a telling reveal that gives President Donald Trump and the leaders of the Justice Department he appointed tangible proof that the special counsel was allowed to carry out his investigation without interference.

By contrast, a report that includes explosive revelations detailing instances in which Mueller clashed with his department supervisors — say, over a subpoena for the president or an indictment against a top Trump aide or family member — would open a road map for Democratic lawmakers who have already begun their own investigations into Russian interference in the 2016 elections, as well as the president’s conduct since taking office.

“Either way, it’s significant,” said Sol Wisenberg, a former deputy on independent counsel Kenneth Starr’s investigation of President Bill Clinton. “Assuming Mueller doesn’t indict anybody else, Trump will be able to say this guy wasn’t kept at all from going anywhere he wanted to go. So I think that’s a big deal.”