My post with emphasis added by Horatius:
My point is - there might be no useful orders for Biden to give to the military.
If Trump stays in the White House, it would not be up to the military to evict him, that's a role of a civilian department - currently headed by loyal Trump appointees.
If Trump's cabinet officials retain possession of their offices and continue to give orders to the civilian bureaucracy, there may be no role in the military for ending that.
If civilians in Government agencies get orders from two sets of bosses, one of which (Biden's team) can't access agency buildings or electronic communications - who do they follow? There is no role for the military to resolve that.
They'd either follow Biden's orders, or not do anything at all. This idea that the Old Boss will just show up and act like he's still in charge is nonsense. Every government employee will be aware that the new President has been sworn in, and won't just ignore that.
If there is some small cabal of high-level officials who try to pull this off, and the civilian law enforcement agencies refuse to do anything about that, then these officials and the law enforcement agencies supporting them will be in de facto rebellion against the lawful government of the United States. And kicking a bunch of rebels out of government facilities that they're illegally occupying is exactly a job for the US military.
And enough members of the FBI and USSS are former military that they'll know exactly what will happen to them if they make the Army storm the Whitehouse or some other Washington facility. The USSS may be heavily armed when compared to your average police force, but they'll melt like snow on a stove top when the military takes them on.
You emphasized the wrong point here. I am not advocating disaster porn, I don't think any of this would actually happen - but I also see no role for the military in ensuring the transition of civilian government. The emphasis goes more like this:
If civilians in Government agencies get orders from two sets of bosses, one of which (Biden's team) can't access agency buildings or electronic communications - who do they follow? There is no role for the military to resolve that.
I agree that the civilian bureaucrats would follow Biden's orders - but in such a
hypothetical situation, that could be delayed if Biden's teams lacked access to facilities and communications. One team would be sending out emails and instant messaging from govvie accounts, the other team using gmail accounts, no access to internal instant messaging, not knowing cell numbers to reach agency employees working from home. Both sides citing laws and legalese as reason why gov employees should only listen to "our" side, not the "other" side, with threats to those who don't comply. Gov employees getting emails from gmail or other civilian email accounts giving them orders, signed by people they might never have heard of - yet those unknown people with the civilian accounts might actually be the legitimate leadership.
That won't happen, part of the transition process (which GSA is currently enacting) is that senior officials get access to such accounts functional on day one. But if a sitting outgoing loser President and his cabinet and other appointees went full refusenik (preventing GSA from enabling pre-inauguration transition activities
*, going so far as to go judge shopping until they find one willing to swear in fake-POTUS for a second term), the role of the
military in ensuring transition of civilian departments would be limited to none.
The transition would happen anyway, but not through military force. It would be a muddled and slow and confusing transition, devoid of military involvement.
I really don't see a role for the military in this. If we open the door to using the military to ensure post-election transition, we may not get that door closed again.
* In our modern system, the keys to power are held by the IT staff setting up (or removing) email and network profiles, granting (or denying) access to clouds and servers and instant messaging, activating (or deactivating) card keys needed to log into the computers also granting access to buildings. In a disputed transition, those people would be ones getting the harshest pressure. Again, this is not something the military would have a role in.
