We are an exceptional nation but entirely an accident. Our Constitution is the only real constitution in the world. It was self imposed at a time when the notion of a constitution to limit government was in vogue. That vogue passed away. No other people ever chose to protect or entangle themselves with such a constitution. And a Bill of Rights.
Yet for us, the Constitution has created a text centered people, just like the Diaspora Jews. The Jews had the text center of the Torah, the sacred words forever to be debated and reinterpreted. For 2,000 years the Jews have been without a government, a disconnected but coherent people studying a sacred text from the past and living in the present under a wide range of circumstances always re-interpreting the sacred text.
The same is true for Americans. Our sacred Constitution holds us together despite having a weak, and at times incompetent, central government, trying to cope with 13-50 separate state governments.
Our separate states slowly conferred power on the central government, but never very much. To this day we have a weak central government compared to most other industrial governments. Look at the 2008 financial crisis and the fact that we still have no rational plan to remedy that pathetic national incompetence. We probably never will remedy our incompetence. Remember that the 1913 Federal Reserve didn't have teeth until the 1950s. It is still ineffective and completely failed our financial structure in 2008.
Had this American socio-political experiment occurred anywhere else, but safely sequestered across two large oceans, the neighboring countries would have taken advantage and swooped in for control. This would have destroyed America many times as the states and the national government squabbled (1812, 1846, 1863, 1898, 1916, 1939, 1953, 1963, 1973).
Truly an accident but a fortuitous one for those of us who love commerce.