What is the most important similarity of the Joe Biden and Donald Trump classified documents investigations? Of course, there is the simple fact that both men, the current and former presidents, are accused of mishandling classified information. But just as critical, from the public's perspective, is this: We don't know what that information was. We don't know if the classified material each allegedly mishandled involved the nation's most sensitive and carefully guarded secrets, secrets that would do grave damage to national security if revealed, or whether it was minor stuff that should never have been classified in the first place.