[FreedomPoster]

It is worth noting that the Japanese very much learned from the British, who took out the Italian fleet at Taranto harbor in 1940 in a sneak attack. With Fairey Swordfish! (Look it up).

That the US Navy got taken out in a highly similar attack a year later did NOT reflect well on the Navy.

[zek157]

The Japanese started the 1904 Russo-Japanese war with a surprise attack on Port Arthur too. Wouldn’t have been much of a reach to believe they could it again.

[Rockingham]

Due to the Taranto attack, the US Navy command warned of the risk but the local commander in Pearl Harbor, Admiral Kimmel, thought that torpedo nets were unnecessary due to the shallowness of the anchorage.

Bill Halsey thought otherwise and got his carriers out to sea on a resupply mission. Halsey knew or suspected what was coming and had his ships on wartime alert conditions.

There were other warnings. The German Abwehr sent a spy, Dusko Popov to the US. Part of his assignment included finding out the details of Pearl Harbor's defenses.

Popov contacted the FBI and offered to become a double agent. Although he reported the intended attack on Pearl Harbor in August of 1941, there is no record of action by Hoover.