sentences:  Historians have observed that while the Doctrine contained a commitment to resist colonialism from Europe, it had some aggressive implications for American policy, since there were no limitations on the US's own actions mentioned within it.Scholar Jay Sexton notes that the tactics used to implement the doctrine were "modeled after those employed by British imperialists" and their competition with the Spanish and French.Eminent historian William Appleman Williams described it as a form of "imperial anti-colonialism."