The inability of the League of Nations or the United States to prevent the Italian invasion of Ethiopia emboldened Japan and Germany to pursue their territorial ambitions. After the Marco Polo Bridge Incident, Japan invaded China in July 1937, capturing Chinese capital of Nanjing (or Nanking) before the end of the year. The Nanking Massacre and the USS Panay incident both outraged Americans, many of whom had an affinity for China due to cultural works like "The Good Earth", but the Neutrality Acts blocked arms sales to China. In a reflection of the continuing strength of isolationism, the Ludlow Amendment, which would have required a national referendum for any declaration of war, was only narrowly defeated in the House. Roosevelt gained world attention with his October 1937 Quarantine Speech, which called for an international "quarantine" against the "epidemic of world lawlessness." He did not at this point seek sanctions against Japan, but he did begin strategic planning to build long-range submarines that could blockade Japan.