"This is very significant. I’ve never seen anything like it."

The title of this post is lifted from a Twitter message from Neal Katyal, American lawyer & partner at Hogan Lovells, and other bona fides including having argued more Supreme Court cases than any other minority group lawyer in American history. In 2017, American Lawyer Magazine named Katyal its coveted Grand Prize Litigator of the Year for both 2016 and 2017.
After linking the Washington Post article, he continues...

Signers incl "Donald Ayer, a former deputy attorney general in the George H.W. Bush Administration; John S.Martin, a former U.S. attorney and federal judge appointed to his posts by two Republican presidents; Paul Rosenzweig, who served as senior counsel to Kenneth W. Starr"+more

And this truly is a remarkable story/document.

More than 370 former federal prosecutors who worked in Republican and Democratic administrations have signed on to a statement asserting special counsel Robert S. Mueller III’s findings would have produced obstruction charges against President Trump — if not for the office he held. 

The statement — signed by myriad former career government employees as well as high-profile political appointees — offers a rebuttal to Attorney General William P. Barr’s determination that the evidence Mueller uncovered was “not sufficient” to establish that Trump committed a crime. 

Mueller had declined to say one way or the other whether Trump should have been charged, citing a Justice Department legal opinion that sitting presidents cannot be indicted, as well as concerns about the fairness of accusing someone for whom there can be no court proceeding. 

“Each of us believes that the conduct of President Trump described in Special Counsel Robert Mueller’s report would, in the case of any other person not covered by the Office of Legal Counsel policy against indicting a sitting President, result in multiple felony charges for obstruction of justice,” the former federal prosecutors wrote.
“We emphasize that these are not matters of close professional judgment,” they added. 

“Of course, there are potential defenses or arguments that could be raised in response to an indictment of the nature we describe here. . . . But, to look at these facts and say that a prosecutor could not probably sustain a conviction for obstruction of justice — the standard set out in Principles of Federal Prosecution — runs counter to logic and our experience.”