On the matter of revoking the security clearances of certain senior government officials after they’ve left office—the Trump administration’s thinking about doing that with former CIA Director John Brennan, former FBI Director James Comey, et al., and the associated flap come to mind—former Deputy State Department spokesman Adam Ereli has a point.  Such a move would ring alarm bells, and one alleged motive for doing so raises this problem identified by Ereli:

I think that we’re going down a slippery slope.  Who’s to decide what’s political and what’s not political?

He’s right.  However, the wrong motive does not make the move wrong.  These folks are no longer employees of the Federal government, and so they no longer have the need to know that is one of only two Critical Items in granting a security clearance.  Nor should they have access to classified material—the other Critical Item in granting a clearance.

The right answer here is a blanket one.  All persons, on leaving government employ, should have their security clearances completely revoked; they should not have any security clearance at all.  If government needs to consult a particular individual—a senior official, like an ex-CIA Director, for instance—on a particular matter, it’s perfectly straightforward to (re)vet such an individual and grant him the clearance regarding that item which he needs in order to advise effectively on it.  The vetting and granting process could streamlined further by putting in place protocols optimized for just such a situation with just such a set of ex-senior government persons.

Similarly, it would be easy enough to grant, under the same protocols, limited clearances of limited duration to ex-Presidents so they can assemble their Presidential libraries.