The marines land, and stay nineteen years

American marines landed at Port-au-Prince on 28 July 1915 and did not leave until 1934. Robert Rotberg wrote that the decision was no sudden or capricious response to Haitian political and financial destitution, and that it is more surprising the Americans waited as long as they did. That is right and it is only half the ledger. This was not simple dollar diplomacy either, because American business in Haiti at the time was thin. The drivers were the German commercial community, the Môle Saint-Nicolas harbor, the wartime Caribbean, and the customs receipts already pledged to foreign creditors under the arrangements traced back to 1825. The occupation built roads and a constabulary, rewrote the constitution to permit foreign land ownership, and reinstituted the corvée, which is forced labor. It also produced Charlemagne Péralte and the Cacos, and it produced the noiriste intellectual reaction that arrives in the palace in 1957.

The fighting stopped on 11 November 1918. The war had lasted 1,563 days, killed some ten million soldiers, wounded twenty million more and consumed over three hundred billion dollars. It destroyed the Hohenzollerns in Germany, the Hapsburgs in Austria and the Romanovs in Russia, and in its final hours new governments were forming in Vienna, Warsaw, Budapest, Prague and Dublin while crowds filled the streets of Berlin and Petersburg. Kennedy opens his history of the American 1930s at this date because Herbert Hoover opened his memoirs the same way. The first sentence of those memoirs states that the primary cause of the Great Depression was the war of 1914 to 1918. Everything that followed for the United States, the debt, the tariffs, the closed door to immigrants and the refusal to join the League of Nations, was a reaction to those fifty two months.

During the first United States occupation of Haiti, which ran from 1915 to 1934, opposition in the countryside was often led by Vodou priests and priestesses. Bellegarde-Smith puts the number of Haitians who died fighting the invading army at perhaps fifty thousand, and describes the religion as the popular vehicle of a wider culture of refusal. He reads the missionary side of the occupation as policy. Detaching Haitians from Roman Catholicism and from the French hold on the Haitian elite was expected to turn enemies into friends, and the written record of the period carries the argument openly. Washington had tried the same approach in Puerto Rico after 1898, where replacing Spanish and Catholicism with English and Protestantism was supposed to pacify the island. The French bishops who ran the Haitian church were nervous accordingly. Decades later Francois Duvalier replaced every French bishop with a Haitian of his own choosing and brought American fundamentalist Protestants in against Rome.

Three Marine companies climbed to the crest through the night of 17 November 1915 and attacked on Butler's whistle. Under the walls the twenty four men of the storming party found the entrance bricked over. The only way in was a masonry drain four feet high and fifteen feet long with a Caco sentry firing down it. Three men, Butler among them, crawled through and came out unhurt into about seventy defenders. They fought at the drain mouth long enough for the rest of the party to get inside. The Cacos had machetes, sticks and stones. Their leader, known as General Josephette, was killed in his usual black frock coat, top hat and brass watch chain. Fifty of his men lay dead within a quarter of an hour, and the northern Caco movement died with them. A ton of dynamite brought the fort down afterwards. Pierre-Paul, one of the fiercest Haitian critics of the Americans, later wrote that the Cacos had made an industry of insurrection, raising and wrecking one government after another, and that the wreckage gave the invaders of 1915 their pretext.