The Justice Department’s independent inspector general, Michael E. Horowitz, and his team uncovered a staggeringly dysfunctional and error-ridden process in how the F.B.I. went about obtaining and renewing court permission under the Foreign Intelligence Surveillance Act, or FISA, to wiretap Carter Page, a former Trump campaign adviser.

“The litany of problems with the Carter Page surveillance applications demonstrates how the secrecy shrouding the government’s one-sided FISA approval process breeds abuse,” said Hina Shamsi, the director of the American Civil Liberties Union’s National Security Project. “The concerns the inspector general identifies apply to intrusive investigations of others, including especially Muslims, and far better safeguards against abuse are necessary.”…

Most of those targets never learn that their privacy has been invaded, but some are sent to prison on the basis of evidence derived from the surveillance. And unlike in ordinary criminal wiretap cases, defendants are not permitted to see what investigators told the court about them to obtain permission to eavesdrop on their calls and emails.