If, however, the primary purpose of the investigation was to build a criminal case against U.S. persons in the Trump camp, then the use of FISA authorities to gather information by naming foreign entities sounds like “reverse targeting”—tasking collection on a foreign target when your real interest is a U.S. person with whom they’re communicating. That would be, to use the technical term, highly shady even if not unlawful.

Thanks to the Patriot Act, however, FISA authorities may be used in investigations that have a “significant” foreign intelligence purpose, even if the “primary” purpose is criminal prosecution…