What purpose did foreign nations serve to the U. S in the late eighteeth century

The United States fruitfully traded with other European powers such as the Netherlands, Great Britain and Spain throughout the late 18th century as the United States was in such close proximity to these countries colonies, usually adjacent to American land. France also provided close military support during the American revolution with the arrival of Lafayette's army in North America. Many countries throughout Western Europe also provided America with a steady flow of colonists. Key to American expansion in the following century.