Roosevelt clearly understood – and said so at the time – that the new economic embargo could lead directly to war with Japan. As talks to resolve the crisis between Washington and Tokyo went nowhere and clearly deadlocked over the following six months, US Navy and Army chiefs in Washington, with Roosevelt’s knowledge and approval warned their forces in the Pacific to be prepared for war.
Nevertheless, the daring and effectiveness of the Japanese attack on Pearl Harbor took all US policymakers entirely by surprise. The Japanese sank all eight battleships of the Pacific Fleet (Six of them, remarkably were salvaged of which five participated with devastating effect in the 1944 Battle of Leyte Gulf).
Roosevelt ironically had been seeking to provoke a naval war with Nazi Germany in the Atlantic. He regarded the Nazis as a far greater strategic threat to the United States than the Japanese. But both Roosevelt and British Prime Minister Winston Churchill catastrophically underestimated the capabilities of the Japanese army, navy and naval air force. Had they not made that mistake, they would not have been so ready to carelessly provoke Tokyo into a full scale war.
The lesson for all the armchair hawks who dominate the Republican and Democratic sides of both chambers of Congress today should be clear. US politicians and policymakers and pundits see their endless rounds of sanctions on Russia as a risk free, safe way to weaken, humiliate and eventually to undermine a country and economy whose capabilities they grossly underestimate and despise.
via Strategic Culture One Minute to Midnight: Latest US Sanctions Propel Nations Towards Risk of War