[jackbob]

Which proved that exceptions to the rule of law, and to Constitutional principles, do not work.

Two verbs in same sentence (not a criticism - I often do it). But your meaning is unclear as to what you meant by "do not work." Please explain.

[P_A_I]

Slavery was a flaw, an exception, in our Constitutions original principles.. It didn't work.. As made evident by the civil war.