First, Flynn’s statements to investigators were equivocal. That creates significant questions about whether inaccuracies in his description of the Kislyak discussions were honest failures of recollection, not lies. The interview happened about a month after the Kislyak communications. In the interim, Flynn had hundreds of conversations with foreign counterparts. It would have been a challenge for anyone to remember the words of a conversation under those circumstances; and, in their legerdemain, the FBI strategically refused to refresh Flynn’s recollection by playing recordings or showing a transcript.
Second, the FBI and prosecutors took inconsistent positions on whether Flynn intentionally misled them. The interviewing agents believed he was truthful, if forgetful. Director Comey reportedly said the question of whether Flynn lied was a “close call.” Assuming this is so, a close call is not proof beyond a reasonable doubt.
Third, the agents went out of their way to deceive Flynn about the purpose of the interview, at which they hoped to trip him up.