Nothing will change the outcome of the two-year national nightmare known as the Mueller investigation but House Democrats are apparently ready for one more disappointment.

At their request former special counsel Robert Mueller is scheduled to publicly testify before two committees July 17. What new information, exactly, do they expect to yield that wasn’t spelled out in the nearly 500 pages of Mueller’s report? House Intelligence Committee head Adam Schiff said Wednesday that Democrats will “be asking questions that are outside the report.” But unless Mueller has changed his mind, they won't get what they're looking for. He explicitly said in May that “any testimony from this office would not go beyond our report” and that “it is important that the office’s written work speak for itself.”

Democrats are hellbent on pursuing an obstruction of justice case over a crime that didn’t even occur, according to that report. And there is almost no chance Mueller will to help advance them in that cause. (And if he does, it will only make people think that the fix has been in from the beginning.)

Mueller said in his report and in his statement after it was released that he was never going to make a judgment as to whether the president had committed a crime. The responsibility was left up to Attorney General William Barr and his deputy, Rod Rosenstein. After reviewing the report, they determined that there wasn’t enough evidence to pursue an obstruction case, particularly in light of no initial crime (conspiracy with Russia).

The report lays out several episodes where Trump unsuccessfully attempted to curb the special counsel’s investigation and the reasons why he may have done it. One possibility mentioned in the report is that Trump believed the probe was eating in to his political capital and hampering his ability to work with Congress and manage relations with Russia.

There is nothing left to learn. Mueller led an exhaustive investigation with an unlimited budget and power. He came up with some useful indictments of Russian malefactors, but he decided Team Trump had nothing to do with any of that.

Democrats have been through this already. The summary of Mueller’s report came out and they were disappointed. The full report came out and they were disappointed. Mueller delivered a statement to reiterate what the report said, plus he said he was confident in William Barr’s conduct, and Democrats were again disappointed.

Now Mueller will give testimony and assuming he remains consistent, and there’s no reason to believe he’s ready to blow up his own credibility, Democrats will again be disappointed.