Again, you don't seize power by attacking a particular meeting. If Pence had somehow used ritual features of the rulebook and declared the electoral college in

Again, you don't seize power by attacking a particular meeting. If Pence had somehow used ritual features of the rulebook and declared the electoral college invalid, then this would have been a coup (or "self-coup") by the Republican Party. Pence would only have done this if (besides an inclination to "kill democracy") he had secured the allegiance of a number of institutions and set in place the actual conditions for a functioning Trump dictatorship. Coups are frequently preceded by mass demonstrations clamoring for something radical to be done. But these are not "the seizure of power by a political faction"; they're (1) a symptom of the generalized social dysfunction under which a coup is even thinkable and (2) a legitimizing excuse that new rulers-to-be can invoke to minimize general opposition to their claim to power. The seizure of power takes place elsewhere. Sometimes this is even gradual -- in preparation for a coup, loyalists are put in charge of major institutions, particularly security ones: National Guard, branches of the military, intelligence agencies and so on. What you had was a protest. An ugly one too; not all protests are "mostly nonviolent".