It was most successful in Pax Romana. It was hard to maintain because of all the people and enemies.
Enlightenment was still a very masculine enterprise, and it represented, as the previous leading philosophy did, mostly the views of men. Women might have been critical of Enlightenment because they felt that it does not represent the whole population, but only the views of the male population.
The answer is commerce, trade, and industrial production.
The states still had the freedom to create their own laws and have their own constitutions (as long as they don't go against by the Constitution). The states have reserved powers.
The rights of the individuals are respected mainly by being listed in the constitution's first ten amendments, or Bill of Rights.