3. Before the Constitution was ratified. That's not to say that America wouldn't continue to be fairly great for many, many decades to come, but that I believe was the pinnacle. It was an era before political parties; when government ruled lightly and when America was not entangled in foreign alliances or conflicts. A time when each state was almost its own autonomous nation, and the citizens of any given region were seldom subjected to sundry laws and regulations crafted by malignant politicians and bureaucrats from an imperial capital hundreds our thousands of miles away.
Of course, it was flawed and was hardly a utopia, but it was a time that I feel was far to superior to the centuries that have succeeded it in regards to America's governance.
On its own, possibly, but nothing occurs in a vacuum. Some foreign power, probably more oppressive than Britain would have ended up carving up such a disorganized and chaotic mess. A good example is that even after the Constitution was ratified, there was a plot to have Kentucky secede and join the Spanish Empire.