Kimberley Strassel: Did the FBI place a mole inside the 2016 Trump campaign?

The Department of Justice lost its latest battle with Congress Thursday when it allowed House Intelligence Committee members to view classified documents about a top-secret intelligence source that was part of the FBI’s investigation of the Trump campaign. Even without official confirmation of that source’s name, the news so far holds some stunning implications.

Among them is that the Justice Department and Federal Bureau of Investigation outright hid critical information from a congressional investigation. In a Thursday press conference, Speaker Paul Ryan bluntly noted that Intelligence Chairman Devin Nunes’s request for details on this secret source was “wholly appropriate,” “completely within the scope” of the committee’s long-running FBI investigation, and “something that probably should have been answered a while ago.” Translation: The department knew full well it should have turned this material over to congressional investigators last year, but instead deliberately concealed it.

We’ve barely scratched the surface of the FBI’s 2016 behavior, and the country will never get the straight story until President Trump moves to declassify everything possible.

House investigators nonetheless sniffed out a name, and Mr. Nunes in recent weeks issued a letter and a subpoena demanding more details. Deputy Attorney General Rod Rosenstein’s response was to double down—accusing the House of “extortion” and delivering a speech in which he claimed that “declining to open the FBI’s files to review” is a constitutional “duty.” Justice asked the White House to back its stonewall. And it even began spinning that daddy of all superspook arguments—that revealing any detail about this particular asset could result in “loss of human lives.”

This is desperation, and it strongly suggests that whatever is in these files is going to prove very uncomfortable to the FBI.

Keep reading Kimberley Strassel's column in the Wall Street Journal.

Kimberley Strassel writes the Potomac Watch column for the Wall Street Journal where she is a member of the editorial board. Her latest book is "The Intimidation Game: How the Left Is Silencing Free Speech" (Twelve, 2016).  Follow her on Twitter @KimStrassel.