Political map of North America & the Caribbean 7 December 1941 (Attack on Pearl Harbor): Over the course of 1941, US President Franklin Roosevelt gradually increased neutral America's involvement in the War (World War II): extending the Pan-American Security Zone far across the Atlantic; allowing US destroyers to accompany British ships and hunt German submarines; garrisoning Allied bases from Iceland to Surinam; extending Lend-Lease to the Soviet Union; and freezing German and Japanese assets. The US embargo was too much for Japan, whose war in China (Second Sino-Japanese War) depended on imported oil. On December 7, it launched a surprise attack on the US Pacific Fleet at Pearl Harbor (Attack on Pearl Harbor), bringing America suddenly into the War.