Susan Hennessey, a former attorney for the National Security Agency who is now a fellow at the Brookings Institution, said she had no knowledge as to whether a Foreign Intelligence Surveillance Act warrant had been issued in the investigation of Russian influence. However, she said such warrants were issued only if investigators could establish “probable cause” that the target was a foreign power or its agent and that the surveillance was likely to produce foreign intelligence. She said the information in Steele’s dossier couldn’t have met that test.