The institutional memory and expertise of past national security appointees/employees in all probability has in the past and will again in the future play an important, perhaps essential role in defending our country against who knows what (not that we'll ever know). Just an example: current CIA boss calls up her predecessor and says, 'X & Y surprisingly transacted with W & B and then C happened in country T - you dealt with X & W extensively and the undersecretary of finance in T is someone whose recruitment your oversaw - what do you make of all this?' Stupid example maybe, I've been reading spy novels, but you get the idea - without security clearance, the patriots no longer employed but retaining their expertise and personal experiences cannot be consulted and that could have very serious, even extreme consequences for all of us.