Preface: We don’t contest that World War II was – in many ways – a “good war”.
The Nazis, imperial Japanese and fascist Italians were nasty folks trying to take over the world, who brutalized millions within their own borders and in the nations they occupied.
But a full an honest account of World War II shows that some big American banks funded the Nazis . And America dropped nuclear bombs on Japan when top U.S. military officials said it wasn’t needed .
And – as shown below – we probably knew about the coming Pearl Harbor attack, but let it happen to justify America’s entry into World War II.
The White House apparently had – a year before Pearl Harbor – launched an 8-point plan to provoke Japan into war against the U.S.  (including, for example, an oil embargo). The rationale for this provocation is that the U.S. wanted to aid its allies in fighting the Nazis and other axis powers, and decided that an attack by Japan would be the most advantageous justification for the U.S. to enter WWII.
Moreover, Honolulu newspapers warned of a possible attack by the Japanese on Pearl Harbor:
Indeed, as the following must-watch BBC documentary – with interviews with many of the main players, including military officers and code-breakers – shows, the American and British knew of the Japanese plan to attack Pearl Harbor — down to the exact date of the attack — and allowed it to happen to justify America’s entry into World War II:
And see this short essay  by a highly-praised historian  summarizing some of the key points. (The historian, Robert B. Stinnett, a World War II veteran, actually agreed with this strategy for getting America into the war, and so does not have any axe to grind).
Active Interference with Military’s Ability to Defend
It has also recently been discovered that the FDR administration took numerous affirmative steps  to ensure that the Japanese attack would be successful. These steps included taking extraordinary measures to hide information from the commanders in Hawaii about the location of Japanese war ships (information of which they would normally be informed), denying their requests to allow them to scout for Japanese ships, and other actions to blind the commanders in Hawaii so that the attacks would succeed. See, for example, this book  (page 186).
Key Military Players Incommunicado
In addition, the heads of the Army and Navy suddenly disappeared and remained unreachable on the night before Pearl Harbor. And they would later testify over and over that they “couldn’t remember” where they were  (pages 320 and 335).
Two weeks after Pearl Harbor, the Navy classified all documents top secret, and the Navy Director of Communications sent a memo ordering all commanders to “destroy all notes or anything in writing” related to the attacks. More importantly, all radio operators and cryptographers were gagged on threat of imprisonment and loss of all benefits.  (page 256).
Scapegoating and Labels of “Conspiracy Theory”
The commanders in Hawaii, General Short and Admiral Kimmel, were scapegoated as being the cause for the “surprise” attack on Pearl Harbor (they were recently cleared by Congress).
And, according to a statement made to me privately by a leading Pearl Harbor scholar, the government repeatedly denied foreknowledge and labeled anyone who discussed the military’s prior knowledge of the attacks as a nutty conspiracy theorist.
Amazingly, the Army’s Chief of Staff informed the Washington bureau chiefs of the major newspapers and magazines of the impending attacks before they occurred, and swore them to an oath of secrecy , which the media honored (page 361); and listen to interview here  (we personally spent an hour speaking with Stinnett, and find him to be a highly credible and patriotic American.)
Postscript: Coincidentally, Philip Zelikow, the Executive Director of the 9/11 Commission, the administration insider whose area of expertise is the creation and maintenance of “public myths” thought to be true, even if not actually true , who controlled what the 9/11 Commission did and did not analyze, then limited the scope of the Commission’s inquiry so that the overwhelming majority of questions about 9/11 remained unasked , also happened to be the main guy defending the alleged unforeseeablity of the Pearl Harbor attack, who wrote a hit piece on Pearl Harbor historians  like Stinnett.
It has been proven that 9/11 was entirely foreseeable  and yet – unexplainably – all of the key military players just happen to have been unavailable and out of the loop when they were needed  (and see this ).
But that’s just an interesting coincidence, because countries never use false pretenses to launch wars. Well, almost never , especially when it involves the innocent killing of our own people .