The underappreciated story right now is that w e’ve not only learned that it was Mr. Barr — and pointedly not Mr. Mueller — who decided to clear President Trump of the obstruction charges, but also discovered the reasoning behind Mr. Barr’s decision. The American public and Congress now have the facts and evidence before them. The sunlight the regulations sought is shining.

Mr. Barr tried to spin these facts. He hid Mr. Mueller’s complaints, which were delivered to him in writing more than a month ago, even when Congress asked in a previous hearing about complaints by members of the special counsel's team. And the four-page letter that Mr. Barr issued in March and supposedly described the Mueller report omitted the two key factors driving the special counsel’s decision (which were hard to miss, as they were on the first two pages of the report’s volume about obstruction) : First, that he could not indict a sitting president, so it would be unfair to accuse Mr. Trump of crimes even if he were guilty as sin; and second, Mr. Mueller could and would clear a sitting president, but he did not believe the facts cleared the president.

These two items came out because the special counsel regulations allowed for public release of this information (and not, as Mr. Barr testified on Wednesday, because he “overrode” the regulations to give the information to the public). The attorney general was misleading through and through, not just about the investigation, but about the special counsel regulations themselves.

What’s more, we now know about Mr. Barr’s reasoning to clear the president, which turns out to be painfully thin. When asked on Wednesday why he did so, Mr. Barr said the Department of Justice ordinarily issues “binary” decisions: indict or not indict. But Mr. Barr’s own view is that this case is anything but ordinary, because the president cannot be indicted. If Mr. Trump were an “ordinary” individual, he’d almost surely be looking down the barrel of a federal indictment right now. So how can Mr. Barr now use the “ordinary” rules playbook?

This mishmash of legal arguments is absurd. No responsible scholar who thinks a sitting president cannot be indicted also thinks an attorney general can try to truncate a process of oversight — by Congress, for example — by “pre-clearing” the president in advance. The whole idea behind the notion that a sitting president cannot be indicted is that the responsibility lies in Congress. An attorney general shouldn’t put his thumb on the scale one way or the other. That’s why Mr. Mueller’s predecessors, Kenneth Starr and Leon Jaworski, simply served the evidence up to Congress; they didn’t try to exonerate the president in advance of it.