From “An Indigenous Peoples’ History of the United States” by Roxanne Dunbar-Ortiz
The instability of the impoverished new republic of Mexico, as it emerged in 1921 from more than three centuries of Spanish colonialism and an exhausting war of national liberation, put it in a weak position to defend its territory against US aggression. With Spain out of the way, the United States could pursue its own policy of imperialism without risking a difficult war with European imperialist powers – when Geroge Washington had referred to in his farewell address when he warned against “foreign entanglements.”