Milgov.

1. I think Civil Affairs Officers and commands would become more important. In a cantonment, they would probably be the main liaison with civilian authorities in the areas. The relations would probably vary depending on what the situation was like. If there was relatively organized territory where mayors were still being elected or whatever local equivalent existed, if there was a governor or equivalent, then this would probably be a kind of partnership. The military would in some cases have seniority over production of important goods or products, in other cases they might be just defending the territory.

I also think that in some cases where there had been utter chaos, the military would have replaced the civilian governments locally. Perhaps they might be slowly built up. This would range from virtual proconsul like commanders in some areas to Milgov providing protection and support.

2. Generally Support command officers would have a totally different approach to providing support for the need to do a wide range of supplies that regular procurement contracts would not fill. They might have special units attached solely for maintaining a fuel refinery or ammunition production factory, water purification plant, etc.

3. Where possible, I picture Milgov having a Recovery Support (Unit) which would assess the viability of areas around contonments or field commands, establishing whether the area needs to be evacuated, if key infrastructure can be rebuilt and so on. This would also include future projections about a census and possibility of rebuilding the government.

4. Generally, for the near future, I imagine Milgov accepting the idea that there will be no presidency, and so the Chairman would be presented to those under Milgov as an ad hoc emergency government for the interim.

A possible alternative of course is some government agency--FEMA, the Director of an Agency on the National Security Council, etc--but the problem is that they might not have the legitimacy in the minds of military personnel unless they have shown a keen organizing ability and have won over the Joint Chiefs and other senior personnel.

5. Defense Agencies may still have installations or projects that are active. These may need direct assistance, rescuing and so on.

Civgov

1. CivGov might very well have appointed the regular cabinet, senior government agencies and so on. The staff would probably be a lot smaller. I picture the remaining agencies like a kind of Praetorian Guard for the Presidency.

- The CIA
- The FBI/ATF/DEA
- The NSA
- National Science Foundation
- NOAA (which has its own ships and facilities)

2. If you have seen the show "Borgia" the cardinals meeting are often a small group and I picture "Congress" being similar. As stated in canon some may not even properly represent their states. So I picture this being a hodgepodge of hangers on, courtiers, ne'er do wells and such. Or perhaps as in the last days of the Roman Republic, scattered, barely any authority save for those who represent states still relatively efective perhaps.