Fanatics can justify any action, and House Intelligence Chairman Adam Schiff this week demonstrated where that mindset leads. In his rush to paint Donald Trump as a lawbreaker, Mr. Schiff has himself trampled law and responsibility.

That’s the bottom line in Mr. Schiff’s stunning decision to subpoena the phone records of Rudy Giuliani and others. Mr. Schiff divulged the phone logs this week in his Ukraine report, thereby revealing details about the communications of Trump attorneys Jay Sekulow and Mr. Giuliani, ranking Intelligence...