he probably does not know what that is. Find out if he ever signed one. did he sign the one to go into Pakistan, or did valerie, or the signature machine?
He (Obama) didn’t need to know what the CBA was .. it would be prepared and put before him to sign.
He can, of course, ask what the document is .. and when he’s told .. he then has to make the decision to sign or not.
So, the people who presented him with the document are too cowardly to come forward and tell the truth.