Answer:
True.
By 1783, which is the year that marked the end of the American Revolution, the United States was arguably the most democratic country in the world.
Explanation:
The American Revolution was not only a military revolution, but also a deeply political one: it created a new system of government based on the ideas of Republicanism, Representative Democracy, Liberalism, and Federalism.
These were ideas that had already been explained in written form by some authors (for example, John Locke), or that had been put in practice in ancient times (for example, in the Roman Republic, or in the Athenian democracy), however, they had not been put in practice in the form that the U.S. did.