If we're being completely honest, the checks and balances in the constitution ended within the first decade. They were only designed to work in the case that the three branches of government were truly separate and adversarial with one another.
The creation of political parties largely eliminated them, both because they cross-cut branches and because the first-past-the-post, winner-take-all electoral system virtually guaranteed the parties would have nearly even representation most of the time.
That it's greatest likelihood of collapse comes between 236 and 243 years later (depending on whether you count from the end of the revolutionary war or ratification of the constitution) is a goddamn miracle.
