Was Pearl Harbor attack as big of an intelligence failure as 9/11 or was Pearl Harbor used as catalyst to get US into helping Europe in the World War 2?

by phrresehelp
Artrw

I've removed this due to the 20-year rule because of the tie-in with 9/11. You might want to repost this as just "Did the U.S. really have no idea of the War/naval/air capabilities of Japan and did the attack truly came as a surprise to everyone?" which would be acceptable to the rules.