The Americas were named after Amerigo Vespucci, who demonstrated that Columbus was wrong: He hadn’t traveled to Asia; he had discovered the New World.
The New World meant freedom from the old, oppressive powers of the Old World. Not having a proper name, the United States has assumed the name of the New World, America.
The States haven’t kept freedom perfectly, but they have faired well among other countries in the Americas. In the States, Blacks conquered slavery and natives were reserved rather than exterminated.
The great mistake of the States was helping the Old World that didn’t want help.