Rep. Adam Schiff has many talents, though few compare to his ability to function as a human barometer of Democratic panic. The greater the level of Schiff hot, pressured air, the more trouble the party knows it’s in.

Mr. Schiff’s millibars have been popping ever since the Permanent Select Committee on Intelligence, on which he is ranking Democrat, last week voted to make a classified GOP memo about FBI election year abuses available to every House member. Mr. Schiff has spit and spun and apoplectically accused his Republican...