According to Leuchtenburg, Hoover was "the last American president to take office with no conspicuous need to pay attention to the rest of the world". Nevertheless, during Hoover's term, the world order established in the immediate aftermath of World War I began to crumble. As president, Hoover largely made good on his pledge made prior to assuming office not to interfere in Latin America's internal affairs. In 1930, he released the Clark Memorandum, a rejection of the Roosevelt Corollary and a move towards non-interventionism in Latin America. Hoover did not completely refrain from the use of the military in Latin American affairs; he thrice threatened intervention in the Dominican Republic, and he sent warships to El Salvador to support the government against a left-wing revolution. Notwithstanding those actions, he wound down the Banana Wars, ending the occupation of Nicaragua and nearly bringing an end to the occupation of Haiti.