Everything old is new again
Been here, contemplated this... during the Nixon administration. Then, I was young enough to man the barricades. Now, not so young -- but I would take first to the 'pen' (i.e., its digital replacement, the keyboard), then to the streets if necessary.
In 1974, we proved the Constitution was stronger than one man's megalomaniacal dreams of an "imperial" Presidency. That's a more likely scenario than insurrection, armed or otherwise...
But: If such a usurpation of power were attempted, it would definitely qualify as the type of Crisis looked for in Strauss & Howe's cyclical theory of American history -- the very time for the Gray Champions to appear. Hence, my desire to become one, "just in case".