Will be interesting to see what Trump pardons Michael Flynn for. Trump does not know the entirety of Flynn's federal criminal exposure. Flynn might not even be specifically aware of the entirety of his federal criminal exposure.

Re: pre-emptive pardons: Except for amnesties (e.g. Carter's draft resister pardon), the only so-called preemptive pardon that did NOT involve charged crimes was Ford's pardon of Nixon. Ford pardoned Nixon for all federal crimes during his presidency, a five year period.

But, remember, the validity of the Nixon pardon has never been litigated. And, as then NY Rep Liz Holtzman and others have argued, a strong argument can be made that a pardon that fails to specify crimes pardoned is invalid. We should not assume the validity of a blanket pardon.