Executive Privilege

Last Monday, we chose “executive privilege” (in the context of the Federal government) as the topic for Monday, 20 December. I found a pretty comprehensive article on the subject in Wikipedia.

There are a number of ways I can think of to approach this topic, including:

Who should be able to assert executive privilege, and under what circumstances?

In particular, should a former president (he who shall not be named) or a former member of the executive branch be able to assert executive privilege, and under what circumstances?

Do the answers to the previous questions change, depending on which branch of government (Congress or the judiciary) has subpoenaed testimony or documents over which the privilege is asserted? If so, why?

Under what circumstances should a claim of executive privilege be deemed to have been waived, for example by prior publication? Would the waiver apply only in the case of prior publication by the person claiming the privilege?

I’m sure there are other questions that can be raised about executive privilege.