ALex Motyl summarizes the answer to the debate on Crooked Timber both eloquently and effectively:The United States expanded westward in a variety of distinctly imperial ways. But by eliminating local Spanish and Indian elites, extending U.S. military, legal, and administrative organizations into the acquired territories, and populating them with nonnative settlers, American built a state and not an empire. - Revolutions, Nations, Empires, p....