And it was much more than war materials with the lend-lease bill starting in March 1941. The bill also rescued Britain from impending bankruptcy.
In April, British ships started refitting in US ports. On 27 May, Roosevelt proclaimed a national emergency. Three weeks later, he suspended diplomatic relations with Germany and Italy and froze their US assets. In July US troops moved into Iceland, replacing a British garrison, to protect the island and build naval facilities for convoy protection. In September the USN, which had been providing convoy escorts for US vessels for some time, began providing them for foreign ships too.
Make no mistake, the US was hip-deep in the European war before December 11th.
Have a look at the PRE-Pearl Harbor history of: SS America (1939):
- On 28 May 1941, America was called up to service by the United States Navy, while the ship was at Saint Thomas in the United States Virgin Islands. She was ordered to return to Newport News to be handed over to the Navy.
- Two Nazi spies were members of her crew. They obtained information about the movement of ships and military defense preparations at the Panama Canal, observed and reported defense preparations in the Canal Zone, and met with other German agents to advise them in their espionage pursuits.
- The ship was acquired by the Navy on June 1, 1941 to be used as a troop transport.
- On July 16, it took on board 137 Italian citizens and 327 German citizens from the consulates of those nations in the United States which had been closed.
- It then returned 321 American citizens and 67 Chinese.
Meanwhile in the Pacific, BEFORE the Pearl Harbor attack, all ships “West” of Pearl Harbor were operating under “rules of engagement” which had been issued in late November which essentially put them on war footing. Which is why the USS Ward fired the first shot of the Pacific war when it sank a Japanese midget submarine. USS Houston had rushed to Subic bay for a minor retrofit of AA guns and radar, but didn’t get the radar because some parts of it were late coming and she had to sail on the 5th to form up with British, Dutch and Australian units to meet a Japanese move south. The Battleships at Pearl Harbor had been oiled for an possible sortie in support of war actions.
What caught the US by surprise was the audacity of the Japanese attack, not that they made it. The US was already in the war.