Two huge elephants in the room that were left out when it comes to presidential transitions. 1. The transition between admins of different parties (1992). 2. The transition between admins of the same party where the incoming president was VP (1988). Kamala's team should not be as naive as you described. She and her advisors have been there for 4 years!
I think we're due for a Cincinnatus moment. Will the Pentagon step up if things get too stupid? You did swear oaths to The Constitution and the political class is currently taking a . . . . all over it. We'll call it the Special Executive Administration, and I nominate HR McMaster to be the CEO. Seat the House and Senate, but a 4-year break on the Executive (which would be appointed) while we restructure the system.
