An oft repeated conspiracy theory asserts officials in the US military had prior knowledge of the Japanese attack on Pearl Harbor and allowed the attack to occur anyway. The conspiracy theorists point to early radar warnings being ignored, the absence of the carrier fleet on the day of the attack, et cetera.

Also, some suggest FDR intentionally held out Pearl Harbor as bait, hoping an attack would shore up support for interventionism.

To state the question clearly;

Does credible historical analysis support the theory that

  1. the United States government intentionally allowed Japan to bomb Pearl Harbor and/or
  2. manipulated circumstances to goad or bait Japan into attacking Pearl Harbor in order to manipulate its population?
  • Point 1 is what we learned in political science education in school … sanctioned, as far as I know, by German education administration departments. Commented Apr 6, 2011 at 12:23
  • @Konrad: East German or West German?
    – Golden Cuy
    Commented Apr 29, 2011 at 13:45
  • @Andrew I went to high school after the reunification. ;-) So this is not Soviet propaganda. That said, every bundesland (~ state) has its own dept. of education; in my case it was Baden-Württemberg, in the far south west. Commented Apr 29, 2011 at 13:51

2 Answers 2


There were US officers that expected a Japanese air attack on Pearl Harbor, but they were generally low-ranking officers, and you can typically find low-ranking officers who will believe anything. (Gordon Prange, At Dawn We Slept). The best account I've found of exactly what went on is Lee & Clausen's Pearl Harbor: the Final Judgment. There are so many conspiracy theories that it is hard to refute them all in one book, but reading a few good books on the subject will be useful.

One thing that most conspiracy theorists ignore is that the US Army and US Navy sent messages to Pearl Harbor ordering preparation for imminent war ten days before the Japanese attack. It seems to me that, if you warn somebody of an impending attack, there's always the possibility they'll do something about it. Another fallacy that is sometimes used is the confusion of US officials expecting imminent war (which they did) with US officials expecting an attack on Pearl Harbor (which they didn't).

The second question is covered thoroughly in Feis' Road to Pearl Harbor (I haven't found a better source yet). In brief, Roosevelt was dragging his heels on sanctions and the like against Japan, in the hope that the US could stay at peace with Japan. (Roosevelt wanted to get into a war with Germany, and in September 1941 ordered the US Navy to fight the war in the Atlantic (Morison, The Battle of the Atlantic). Roosevelt was advised that the materials sent to Japan would delay US rearmament, and allowed them to be shipped anyway.

The tl;dr version of the above:

No high US official expected an attack on Pearl Harbor.

Roosevelt was taking measures to not provoke Japan, in the hopes that he could avoid that war.

  • great response. ty. part of me wanted to believe the FDR part.. though it didn't seem well founded. Commented Apr 6, 2011 at 4:50
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    "No high US official expected an attack on Pearl Harbor." you provide no evidence for that, but then again such evidence cannot exist as their opinions (or at least not those of ALL of them) were not recorded. It's quite possible that at least some senior officers expected a Japanese attack, and the placement of aircraft in the center of airfields rather than the perimeter was done because of that, but the type of attack expected was different. The expected attack was sabotage, not an air raid.
    – jwenting
    Commented Apr 10, 2011 at 14:55
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    This answer is not properly referenced. Please add citations to support your claims! :-)
    – Sklivvz
    Commented Apr 10, 2011 at 19:23
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    @Sklivvz: Okay, what's proper references in this. Do I need to provide page numbers? In cases like this, the websites are often less reliable than the books. Commented Apr 11, 2011 at 0:04
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    @Sklivvz: There are books that "prove" that there was a Pearl Harbor conspiracy, also. I have a few. My point is that real scholarship (which is exemplified by the books above) is usually in dead tree form. Commented Apr 11, 2011 at 14:21

I was reading John Costello's The Pacific War a few months ago (see here http://www.amazon.com/Pacific-War-1941-1945-John-Costello/dp/0688016200). His analysis of the matter was that the preconditions for war were obvious and its imminence acknowledged, but that the Japanese attack was expected to be directed at the Philippines and not Pearl Harbour, as the American forces in the Philippines had been especially strengthened so as to constitute a direct threat to the Japanese homeland.

I am by no means an expert on the subject but Costello's book (published in 1981) would seem to be a good starting place.

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    I'd add to what you've written that this was before radar and air attacks had to take place in daylight. Because Hawaii is east of the Philippines the sun rises there first, therefore American military thinking was that Japan would never attack Hawaii first because that would give the Philippines bases hours to prepare a defense and even a counter-attack against the nearby Japanese mainland. It didn't work out that way, I think because bad weather kept both sides grounded until the next day. (But don't quote me on that.) Commented Apr 5, 2011 at 21:12
  • Incorrect. Radar had been invented before Pearl Harbor. In fact, the first wave was detected by radar, but believed to be a flight of B-17s that were ferrying in. A night launch and attack would have been possible (as proven later on in the war when it become common), but returning to land on the carriers at night would have been problematic. Commented Apr 11, 2011 at 13:14

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