They were in the United States' backyard, and in some cases under her direct protection. So in many ways it was little surprise when Cuba, Haiti, Nicaragua, Guatemala, Panama and Honduras joined the war on the Allied side in 1917 and 1918. Their involvement in the war was minimal, indeed scarcely noticeable, but it was enough. It earned these small relatively powerless nations—in Haiti's case barely a functioning state—an invitation to sit alongside the Great Powers at the Paris Peace Conference of 1919 and sign the Treaty of Versailles.
While Portuguese-speaking Brazil declared war on Germany in the First World War, the rest of South America held back. In the end no other South American nation joined the fighting. But four - Bolivia, Ecuador, Peru and Uruguay - did break off diplomatic relations with Germany in 1917, in sympathy with US policy and with the Allies in Europe. Their reward was a place at the Paris Peace Conference table and for the first time a chance to play a role on the world stage rather than just in their own backyard.