Democrats look at Special Counsel Robert Mueller’s conclusion that he couldn’t “exonerate” Donald Trump on obstruction of justice charges as vindication for their continued probes of the president.

Republicans pointed to other sentences in Attorney General William Barr’s letter on Mueller’s report to claim vindication of their own, noting Barr found there wasn’t enough evidence to form an obstruction case.

How can one report lead to two such different conclusions? The simple answer: Barr did something no one expected him to do, or at least not so quickly, and that was pass judgment on some of Mueller’s findings in a letter sent to Congress on Sunday.

And he did so in the space of less than 48 hours after announcing he’d received Mueller’s report on Friday.

Now Democrats are crying foul, with the head of the House Judiciary Committee, Jerrold Nadler, calling for Barr to come before his committee to explain himself. Nadler and others say Congress has the prerogative to determine if the president broke the law on obstruction, not the attorney general — a Republican appointed by Trump.

Nadler made clear he plans to pursue his own probe into obstruction, something that could become part of a debate among Democrats about whether to impeach the president.

Barr had promised a quick readout on the “principal conclusions” of Mueller’s work after the special counsel turned in his final report on Friday. Official Washington expected a terse recitation of the top-line facts, with a fuller explanation down the road. Most significantly, Barr reported that Mueller found no evidence of Trump collusion with Russia.

But Mueller was far less decisive on obstruction — citing “difficult issues” of fact and law — but noting that his report “does not exonerate” the president.

So Barr stepped in.

He inserted his own judgment — and that of Deputy Attorney General Rod Rosenstein — that charging Trump with obstructing justice wasn’t warranted, even aside from standing Justice Department guidance that a sitting president can’t be prosecuted.

Barr said simply that the evidence didn’t rise to the level that Trump broke the law. He said in his summary that most of Trump’s actions took place in public view or have been the subject of public reporting.

Barr also said that because there was no criminal activity related to collusion, it would be difficult to prove Trump had corrupt intent in his actions toward the investigation.

For months, Democrats had thought obstruction charges were warranted because of Trump’s overt moves, including firing FBI Director James Comey, his public statements of derision about Justice Department personnel and support for former aides charged with crimes. But demonstrating Trump’s intent in making those moves is a much more difficult task.

Barr doesn’t make it clear in his letter whether Mueller asked him to make a determination on obstruction. It’s also possible that Mueller believed it’s a matter that Congress should decide. Mueller’s spokesman, Peter Carr, declined to comment.

Mueller concluded his investigation without ever asking Trump about his actions. The president’s lawyers wagered that Mueller wouldn’t subpoena Trump for his testimony, opening a legal battle, and refused to answer questions from Mueller related to obstruction, fearing that Mueller could accuse him of perjury if his answers were contradicted by other witnesses.

Barr’s appointment as attorney general was controversial in large part due to his 19-page memo to Rosenstein as a private citizen in 2018 arguing against what he thought was an expansive view of obstruction of justice by Mueller. Barr had specifically argued Trump shouldn’t be accused of obstruction of justice for firing former FBI Director James Comey nor for asking Comey if he could lay off of prosecuting former National Security Adviser Michael Flynn.

He argued that such decisions were within the executive powers held by a president.

During his confirmation hearing, however, Barr told the Senate Judiciary Committee that a president could obstruct justice by actions such as trading a pardon in return for covering up a crime, destroying evidence or suborning perjury.

Barr said at the hearing that his memo dealt with a “narrow” question on obstruction of justice, but Dianne Feinstein, the committee’s top Democrat, told him the memo “shows a large, sweeping view of presidential authority and a determined effort, I thought, to undermine Bob Mueller.”

When Democratic Senator Patrick Leahy challenged Barr, saying the memo read like a job application, Barr called his characterization “ludicrous.”

Barr told the committee he was concerned about a too-expansive view of obstruction.

“What I was worried about is the impact on the department and other agencies. If you say to someone, ’If you, in supervising a case, or handling a case, make a decision with a — for a bad intent, it can be a crime.’ And I thought that that would essentially paralyze the government.”

Once Barr’s summary of Mueller’s findings was released on Sunday, Trump quickly claimed victory, and Democrats may face an uphill battle in public opinion if they choose to take the case further than Barr’s report says they should.

“We knew from his confirmation hearing that Attorney General Barr would never conclude the president obstructed justice, which is why it is critical for Congress to see the full Mueller report and the evidence behind it,” Democratic Senator Sheldon Whitehouse, a Judiciary Committee member, said Sunday in a statement.

Barr indicated in his summary that there’s sensitive material in Mueller’s report that won’t be provided to Congress or made public, probably setting up a prolonged legal battle.