An idealist, Roosevelt was trying to suggest an alternative to war in Europe and Asia by way of a US "quarantine" around agressors like Mussolini who had invaded Ethiopia and Japan that was involved with China at that time. He was seeking an alternative to war. US isolationists responded that he was trying to make the US the world's policeman. He was forced to back down for the moment. On 12 December 1937 the US
Panay (PR-5) was attacked by the Japanese while on patrol killing two officers and 30 enlisted. War was busting out no matter how much effort was being applied on the diplomatic front to keep the "epedemic of agression in check.