During World War II, the American people did not want to get involved in another world war.

So the government needed a serious incident to convince the American people to after all, join WW2....

The Allies cracked the German Enigma device and they knew Japan would attack Pearl Harbor and they let it happen because the USA need an excuse to join the war.

The Allies were able to read German messages (Enigma Device) very early in the war thanks to brilliant work by Polish and British mathematicians. In the 1930s, Polish cryptanalysts (code-breaking experts) copied the German Enigma machine with the help of a German traitor, and solved its letter-scrambling patterns. They later shared this knowledge with France and Britain. Intelligence from decrypted Enigma messages, code-named "ULTRA," was extremely secret, and very few people knew about it. While the Germans never found out the Allies could solve their codes, they suspected it as their ability to sink Allied shipping slipped dramatically in 1942. This led the German Navy to add an additional rotor to their Enigma machines, and the submarine "wolf packs" once again started taking their toll of shipping.

Day of Deceit

The Truth About FDR and Pearl Harbor

"By showing that ample warning of the attack was on FDR's desk and, furthermore, that a plan to push Japan into war"

https://www.perlego.com/book/1209835/day-of-deceit-the-truth-about-fdr-and-pearl-harbor-pdf

Franklin D. Roosevelt was a Freemason and a member of Holland Lodge No. 8 in New York City.

List of presidents of the United States who were Freemasons:  https://en.wikipedia.org/wiki/List_of_presidents_of_the_United_States_who_were_Freemasons

Two days before Pearl Harbor, Japanese code JN-25 named it as the target. Freemason Churchill alone could read it and barred everyone else. In 1983, Britain told historian David Irving: those files aren't coming until the 21st century. Whose interest? Not the public's — his reputation.