I’m not at all sanguine.
Scenario: A hundred or so congresspeople are captured and held hostage. Federal interference keeps the National Guard from showing up; by the time they show up, there are mass casualties. This is entirely plausible.
By the time the terrorists are vanquished, the massacre of legislators is the only news. Trump declares martial law, “until we can sort out what happened.” National guard under his explicit control occupies DC.
For one reason or another, the certification of the votes is delayed. This could be Pence’s directive; it could be McConnell’s; it could be Trump’s. After all, too many legislators were killed, and a vote held now would have too many empty seats. As soon as states appoint replacements for the dead, it’ll be rescheduled.
Martial law continues. The president declares a national emergency. Under this emergency, if any media company attempts to ban the president, the president attempts to nationalize the company under emergency powers. One such power could be “Procedural and substantive limitations in statute granting the President broad authority to create, maintain, protect, expand, or restore domestic industrial base capabilities that are essential for the national defense may be waived”. It’d be legally shaky, but the judiciary is pretty subservient to the executive branch.
Republican state governors delay, or send Republican replacements for Democratic representatives and senators.
False conspiracy theories blaming antifa continue to be pushed via the media.
Trump is itching to declare martial law. He’s already used completely bogus emergency powers to fund his stupid wall. It’s entirely plausible that he’d use a travesty to push the military toward taking control and toward delaying certification of the vote and therefore Biden’s inauguration.
I don’t think the coup would ultimately have succeeded, but it could have been very bloody and could have led to civil war.