Non lawfag here, however, I can see the responses,
"Do the best of my recollection", "do not recall", "not a party the conversation", "relevance", "classified, so cannot comment", "base on counsels advise,no comment", etc, etc, etc … very circular … rather have them ambush the truth.
"Truth is treason in the Empire of Lies", or
"Truth is so precious its surrounded by so many lies"