In this essay, Bill Moyers calls the current shutdown/debt default ploy what it is. Secession by another means.
My only quibble is that it might be more accurately termed nullification, with real roots back almost two centuries back to John C. Calhoun. The refusal of a minority to abide by the democratic process and instead threaten to destroy the state if they don’t hold a permanent veto on anything the majority wants to do.