Revealed: The declassified memo that warned FDR of Hawaii attack three days before Pearl Harbor strike

A freshly declassified memo is shedding new light on a possible tip-off of the Japanese attack and the White House’s slow reaction to it.

The 20-page document to President Franklin Delano Roosevelt appears in a new book December 1941: 31 Days That Changed America and Saved the World.

The memo read: ‘In anticipation of open conflict with this country, Japan is vigorously utilizing every available agency to secure military, naval and commercial information, paying particular attention to the West Coast, the Panama Canal and the Territory of Hawaii.’

It also mentioned how the Japanese were bolstering their spy network and collecting ‘technical information’ for use by its Navy.

More than 2,000 Americans were killed on December 7, 1941, in the surprise attack by hundreds of Japanese war planes.

President Roosevelt called the date one that will ‘live in infamy,’ and the attack itself would propell the U.S. right into World War II.

December 1941’s author Craig Shirley, told USNews.com that there were ‘so many mistakes through so many levels of Washington.

But despite those points, Shirley told the website that it doesn’t necessarily mean that President Roosevelt dropped the ball – just that ‘there were more pieces to the puzzle.’

His book even provides a comparison of the way the Bush administration handled information leading up to the September 11 attacks.

Mr Shirley said: ‘Some things never change.’

 The book also reveals how FDR and his war cabinet considered the option of declaring war on all three axis powers (Germany, Italy and Japan) on the night of the Pearl Harbor attack.

In the end, the United States only went with Japan, citing the idea of isolationism and the nation’s weariness from World War I.

The U.S. would, however, declare war on Germany and Italy later on December 8.

The bombing of Pearl Harbor would remain the worst loss of American life in a single strike until the September 11 atrocities – 70 years later.