I am of course using “coup” very loosely here; they are not planning to have the military impose its will by force. Most of the top brass is highly averse to the idea and moreover harbors personal animosity towards Donald Trump. When personal desire aligns with institutional policy against an idea, that idea has no chance whatsoever.
So this leaves a metaphorical coup and not a literal one. Interestingly, Hitler did not take power via a literal coup, either. He was voted into the chancellorship by the proper constitutional process, then used existing provisions for declaring a state of emergency to make himself dictator. Likewise, a legal coup is the most likely route here.
A coup via the courts is unlikely to succeed, for reasons already elaborated on.
That leaves a coup via the state legislatures, which per the Constitution have the power to appoint electors. In all states, they have chosen to use this power to pass legislation requiring electors to be chosen by popular vote. So changing this will require the Fascist Party (a more accurate name than Republican Party, so I will use it for the remainder of this article) to pass legislation repealing or nullifying the existing provision for choosing electors.
This will require a Fascist majority in both houses of the state legislature, and a Fascist governor. The only states Biden won that satisfy this requirement are Georgia and Arizona. If both of them successfully appoint slates of Fascist electors, Biden’s electoral vote total drops from 306 to 279. He still has enough votes to become president.
At that point, the Fascist-controlled legislature in Pennsylvania might by vote proclaim 20 Fascists to be Pennsylvania’s electors. Note I said “proclaim” and not “pass a bill.” The governor of Pennsylvania is a Democrat, so any such bill that ends up on his desk will get vetoed. Instead, both houses of the legislature must pass proclamation, then the Fascists will go to the Federal courts and argue that their electors are the real ones, because they were chosen by the legislature, as the Constitution literally says.
To which I say: good luck with that. Again, the courts are unlikely to rule the way the Fascists want. There is extensive precedent, going up to the Supreme Court, backing up the legislation that states have passed requiring their electors to vote the way popular majority in their state (or, in the case of two states, their Congressional district) voted. This is how electors have been chosen since the turn of the nineteenth century, i.e. for over 200 years. Its legality is a settled matter.
The Fascists’ hand is not strong enough — yet — to force a coup. Their goal is not to stage a coup now, but to pave the way for the next Fascist president (and there will be one, in 4 to 12 years) to stage a coup later. It is to delegitimize elections in the eyes of their base. And it is working.
The Fascists will eventually get their coup, and those of us who oppose fascism need to use the intervening years until they get it to plan how to resist it. But they will not get their coup this time.