One of William P. Barr’s weaknesses is a godsend for the rule of law: The attorney general is not completely effective at lying. Or at least close observers of Barr have learned over time how to spot his many tricks. Barr’s behavior in his prior career in government and in his current office reveals voluminous and specific examples in which he misled the public and Congress. Within hours, if not minutes, leading fact checkers documented several of Barr’s deceptions in his congressional testimony on Tuesday. And there’s every reason to suspect Barr will soon try again to mislead — this time regarding one of his most important initiatives to date, an investigation by his handpicked U.S. attorney, John Durham — in an effort to skew the 2020 elections.

The problem is that there are two types of lies that Barr is willing to employ. One can be detected quickly. The other often takes time to uncover, and by that point, Barr may already have succeeded in his goal.

Based on Barr’s track record, it’s important for the public to realize now that they can’t take Barr’s word on what Durham actually has found. The urgency of bracing people to disbelieve the attorney general increased dramatically on Tuesday, as Barr was asked whether he’d apply long-standing Justice Department policy not to announce politically sensitive new cases before an election by holding Durham’s findings until after Nov. 3. Barr’s answer was, for him, a rarity in its clarity: He said no.

Durham’s investigation has become Barr’s pet project. Durham’s main task is an investigation of the investigators who tried to understand and protect the United States against Russian election interference in 2016. We don’t know what Durham will conclude, but we’re confident in this: Barr will likely distort those conclusions in a way favorable to President Trump’s political ambitions. That goal seems to have driven Barr’s public anticipation of “developments” from Durham “before the end of the summer” — that is, in time to influence the November election.

Barr has a history of mischaracterizing and even lying about the results of investigations before their details are public. That’s what Barr did to special counsel Robert S. Mueller III’s investigation. The attorney general released his own “distorted” and “misleading” summary while delaying the release of Mueller’s actual conclusions by weeks. Don’t just take our word for it; those are the words of the federal judge who excoriated Barr for his deceit. By the time Barr allowed the rest of the country to see Mueller’s actual conclusions — which were relentlessly damning for Trump — Barr’s mischaracterization of Mueller’s investigation as having exonerated the president had taken hold among key constituencies. And by the time the federal judge ruled on the matter, almost a year had passed. Far fewer Americans were even paying attention.

There were several other flat-out lies by Barr during the course of those events: He misrepresented the role that the Justice Department’s view that a sitting president can’t be indicted had played in how Mueller approached his work, claiming it hadn’t constrained Mueller’s conclusions when Mueller clearly said it had; he told Congress he was unaware that Mueller’s team was upset with his summary of their report, when in fact Mueller had conveyed his concern and frustration to Barr in writing; and he declared that the White House had “fully cooperated” with Mueller, when Trump refused to testify under oath, sit down for an interview or answer a whole set of questions.

Barr’s summary wrought such havoc inside Congress that it likely succeeded in sharply narrowing the articles of impeachment against Trump, according to a book released earlier this week by Norman Eisen, who served as special counsel to the House Judiciary Committee during the process.

That’s far different from Barr’s other lies that implode on impact. Consider a recent example. After meeting in person with U.S. attorney for the Southern District of New York Geoffrey S. Berman and failing to coerce Berman’s resignation, Barr nonetheless announced publicly that Berman had stepped down. When Berman set the record straight that evening with a public statement that he had not in fact resigned, Barr was forced to regroup and, ultimately, name a different successor to Berman — the one mandated by law — before Berman then agreed to resign. The most remarkable part of the whole episode was Barr’s brazen and easily disprovable public lie, and how quickly it was exposed thanks to Berman.

Yet none of these past incidents seems as near and dear to Barr’s heart as what’s still to come: the conclusion of the Durham investigation. It’s an investigation no ordinary attorney general would have ordered in the first place. Criminally investigating the investigators without any apparent wrongdoing is a bizarre step to take, and the very issues being explored by Durham already have been investigated by the Justice Department’s inspector general, who found that the opening of the Russia investigation (code-named “Crossfire Hurricane”) was properly predicated, with no evidence it was influenced by political bias. Yet Barr has pressed ahead — hard — with demanding that Durham investigate the FBI and, apparently, even other components of the intelligence community for their counterintelligence work in 2016. In a wild step for an attorney general, Barr has reportedly personally traveled the world to urge foreign governments to cooperate with Durham.

There are signs that Barr has already enabled Durham’s unorthodox behavior, which could foreshadow his own efforts to distort the public’s understanding of whatever conclusions Durham will reach, whether those take the form of criminal charges, a written report or some combination. When the inspector general issued his much-anticipated report, Durham was in the midst of an ongoing criminal investigation — a situation in which a federal prosecutor should, according to Justice Department policy, refrain from commenting publicly. Yet Durham did the opposite: He released a public statement indicating that, even though he was still conducting his investigation, he disagreed with the inspector general’s conclusions. This was extraordinary, in addition to being a mid-investigation public commentary. It was also a public rebuke of the Justice Department’s inspector general by another department official, and one that, it turns out, was misleading about where exactly Durham and the inspector general differed.

But Barr’s spin works only if others take his word for it or imbue him with the credibility of an attorney general faithfully executing his oath of office. Whatever conclusions Durham actually reaches, Barr’s history indicates that he’ll make them sound better for Trump and worse for the counterintelligence work of America’s public servants. As The Washington Post’s Amber Phillips wrote about Barr’s most recent testimony, takeaway number one is: “He is all in as a partisan player.”

When it comes to spin, being forewarned is being forearmed: Don’t buy it. It’s essential that Congress, the media and the public refuse to accept what Barr says at face value. Wait till we see what Durham’s investigation actually concludes — then we can applaud or criticize those results as we all see fit, but at least we’ll elude the grasp of Barr’s distortions.