Attack on Pearl Harbor

Did the American government have advance knowledge of the Pearl Harbor attack, and allow it to happen?

by Brian Dunning

Filed under Conspiracies

Skeptoid #211
June 22, 2010
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Admiral Kimmel at Pearl Harbor
Admiral Husband Kimmel at Pearl Harbor in 1941, at the time he was Commander in Chief of the Pacific Fleet
Photo credit: U.S. Navy

Every schoolchild knows the story of December 7, 1941, "A date which will live in infamy". Japanese aircraft carriers crept to within striking distance of Hawaii and launched a morning sneak attack which struck at 7:55am. Two waves of 354 Japanese bombers, dive bombers, torpedo bombers, and fighters decimated an unprepared U.S. Pacific Fleet. They sank four battleships and two destroyers and heavily damaged eleven other ships, destroyed or damaged 343 aircraft, killed 2,459 servicemen and civilians, and injured 1,282 others. Less than 24 hours after the first bomb fell, the United States declared war on Japan. One question has plagued the conspiracy minded ever since: Was the United States truly caught by surprise, or did the government have advance knowledge of the attack and allow it to happen, as an excuse to declare war?

We should begin by establishing that the overwhelming majority of historians are not moved by this theory. It is promoted really only by a few authors and anti-government activists. However, that doesn't make it wrong. Most Americans have heard the theory suggested, usually in the context of it being an open question. It's not. The jury is not "out" on this one, despite a tiny minority of amateur historians making a majority of the noise. But as we always do on Skeptoid, we'll give the fringe their day and look at their evidence.

Perhaps the most popularly known clue is that the United States' three aircraft carriers were safely out of harm's way. They were out on maneuvers, and were not in port in Pearl Harbor with the rest of the Pacific Fleet. If the American commanders wanted the attack to happen, they would probably still choose to protect their most valuable assets.

Less well known is that a Japanese midget submarine was spotted at 3:42am, four hours before the attack began. A destroyer, the USS Ward, was called in which failed to find that sub, but did find and sink a second sub at 6:37am, still more than an hour before the air strike. The Ward radioed in "We have attacked, fired upon, and dropped depth charges on a submarine operating in defensive sea areas." Would not this action have put the Fleet on high alert, unless someone overruled it?

At 7:02am, a full 53 minutes before the first bomb fell, radar operators at Opana Point detected the incoming Japanese aircraft. They alerted their superior, Lt. Kermit Tyler, who failed to make any report, but did however take his men away from their posts and to breakfast. Tyler's lack of action has long been considered suspicious by the conspiracy theorists.

Indeed, nearly a full year before the attack, the Commander-in-chief of the Pacific Fleet, Admiral Husband Kimmel, wrote to Washington:

I feel that a surprise attack (submarine, air, or combined) on Pearl Harbor is a possibility, and we are taking immediate practical steps to minimize the damage inflicted and to ensure that the attacking force will pay.

Then, ten days before the attack, Kimmel was ordered to make just such a defensive deployment of the Fleet. And yet, on that morning, the ships were sitting ducks at their berths, the men asleep in their bunks, and most of the American aircraft were parked on the fields in plain view, packed into tight bunches, as if to deliberately make easy targets. It's also been pointed out that since the ships were sunk in the harbor, most were raised and repaired. Had they been sunk at sea they would have been lost. If you wanted to be attacked, but also wanted to be able to bounce back, this was the way to do it.

Combined with the fact that the Americans had broken the primary Japanese diplomatic code called Purple and made some progress breaking the military code JN-25, and had access to some Japanese intelligence, it seems hard to reach any conclusion other than the United States knew the attack was coming and deliberately allowed it to happen.

Or, at least, so we might conclude if we considered only the above points. But it turns out that if we examine each of these points not just with a narrow focus to see only the suspicious side, and look at the complete event in context, no good arguments for a conspiracy remain. Most of the points made by conspiracy theorists were raised by the 2000 book Day of Deceit by Robert Stinnett, who really boiled down the innuendo from the preceding 59 years and condensed it into a cohesive conspiracy. However, it should be noted that many more authors (almost all others) find him to be wrong. Chief among these is probably Pearl Harbor: Final Judgement from 1992, written by Henry Clausen. In 1944, the Secretary of War ordered Clausen, then a lawyer in the U.S. Judge Advocate's office, to conduct an independent investigation into what really happened in the days and months leading up to Pearl Harbor, and to find out who screwed up. His report remained top secret until its substance was finally published in this book.

Clausen found plenty of sloppiness, but nothing that could be characterized as a cool, smoothly-running conspiracy. Agencies operated independently, decoding Japanese transmissions and then filing them away rather than sharing them. There was plenty of knowledge that hostility was building, but no experience in how to deal with it and no specific knowledge that it was so imminent. Roosevelt knew as much as anyone, and issued warnings and ordered preparations that were poorly handled all the way down the line.

One thing that conspiracy theorists and historians agree upon is that Admiral Kimmel was unjustly made the scapegoat for Pearl Harbor. Ten days after the attack, he was reduced in rank and replaced by Admiral Nimitz. It's also agreed that he did the best he could given the limited amount of intelligence Washington shared with him, and this is one point where the conspiracy theory simultaneously kicks in and breaks down. Historians say he was held accountable for bad decisions; conspiracy theorists say he was made the scapegoat for the secret orders from Washington. But, nearly everything that happened at Pearl Harbor was on Kimmel's own orders. Let's look at some.

When Kimmel received the order to assume defensive positions ten days before the attack, viable threats at the time were from espionage and sabotage, not actual attacks. Thus the aircraft were moved out into the open and tightly packed, where they could be best guarded against saboteurs. The ships were similarly grouped in the harbor. It was the wrong interpretation of the order, but it was a reasonable one in the context of what Kimmel knew was happening.

How true is it that the three carriers were safely hidden out at sea? Not very. The carriers were not clustered safely together; they were widely scattered throughout the Pacific on separate duties. Being alone out at sea even with their carrier groups, each isolated far away and unable to support one another, was not at all considered safe. The Saratoga was just coming out of a lengthy overhaul in Seattle and was underway to Pearl Harbor via San Diego at the time of the attack, but the Enterprise and the Lexington had in fact been at Pearl and recently sent away. Why?

Kimmel had sent them, separately and on staggered schedules, to deliver Army aircraft to reinforce Midway and Wake islands. Because of the Japanese spy network on Hawaii, great caution was taken to disguise this movement of forces. The Enterprise was scheduled to return by December 5th, at which time the Lexington would leave; Kimmel wanted to make sure that Pearl had coverage from at least one carrier at all times. The Lexington left on schedule, but unfortunately, bad weather struck the Enterprise and kept its group at sea for two extra days, resulting in an unforeseeable 2-day span of no carriers in Pearl Harbor. There was never any mysterious directive from Washington to hide the carriers. Had the weather not intervened, there would have been at least one carrier in Pearl at all times, which was the maximum force available.

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Even so, there's a powerful reason why the absence of carriers would not support a conspiracy theory. World War II was the first time that aircraft carriers proved themselves to be the most important assets in naval warfare. At the time of Pearl Harbor, we'd not yet learned that, and the battleship was considered the most crucial weapon. That's why the Pacific Fleet had nine battleships and only three carriers. Conspiracy theorist descriptions of the battleships as old, useless, and expendable are a misstatement of history. They were the best we had, and their perceived value was such that at the time of the Pearl Harbor attack, six new battleships of the Iowa class were under construction, and a further six of the Montana class were planned. It wasn't until the Battle of Midway in 1942 that we learned the value of carriers, and construction shifted to those.

Was the Ward's sinking of the submarine covered up to prevent an alarm? The Ward's report made it to the desk of the watch officer at 7:15. At 7:30, Kimmel and Rear Admiral Claude Bloch both received it separately by telephone. By the time the Japanese attacked, 25 minutes later, Kimmel and Bloch were still conversing to determine the significance of the sub incident. Kimmel's opinion was that this was probably one more in a long line of false reports of submarines they'd been accustomed to receiving. Five minutes before the air strike, Kimmel ordered the destroyer USS Monaghan to go and verify the Ward's story. The Monaghan never made it. Kimmel's hunch was only conclusively proven wrong in 2002, when the midget submarine's wreck was discovered.

When Opana Point picked up the Japanese attack force on radar, their station was still under construction and was not yet fully operational. It had been staffed but nobody had yet received any training. The serviceman at the scope had, in fact, never used the equipment before at all. Lt. Tyler was a fighter pilot, and this was only his second day at Opana Point, and he had not been trained yet either. When Tyler was informed of the inbound target, he assumed it to be a flight of B-17's known to be inbound on that same course, which was a pretty common event. Since nobody perceived that anything unusual was happening, Tyler famously said "Don't worry about it," and they did in fact all go to breakfast. But once the attack began, they ran on foot back to the radar station and helped as best they could. A 1942 court of inquiry cleared Tyler of any blame, and he went on to have an exceptional career in the Air Force.

Now of course, all this only pertains to what happened at Pearl Harbor on the day of the attack. It doesn't address the much larger question of what President Roosevelt might have known or wanted to happen, or other people in Washington. The reason I don't go into that is that it doesn't matter. Even if this presumed conspiracy to allow the attack did exist, it failed to have any effect where the rubber meets the road. No orders from Washington altered the state of readiness at Pearl Harbor. Obviously the attack ultimately did play into the hands of anyone who wanted war with Japan; every tragedy somehow benefits somebody. That doesn't make every tragedy a conspiracy.

Brian Dunning

© 2010 Skeptoid Media Copyright information

References & Further Reading

Borch, F., Martinez, D. Kimmel, Short, and Pearl Harbor: The Final Report Revealed. Annapolis: Naval Institute Press, 2005. 66.

Brewer, B. "The Missing Carriers of Pearl Harbor." Times-Herald. 28 Sep. 1944, Newspaper.

CIA. "Intelligence at Pearl Harbor." FOIA Electronic Reading Room. Central Intelligence Agency, 22 Aug. 1946. Web. 6 Jun. 2010. <>

Clausen, H., Lee, B. Pearl Harbor: Final Judgement. New York: Crown, 1992.

Outerbridge, W. "USS Ward, Report of Pearl Harbor Attack." Naval Historical Center. United States Navy, 13 Dec. 1941. Web. 11 Jun. 2010. <>

Stinnett, R. Day of Deceit: The Truth About FDR and Pearl Harbor. New York: Free Press, 2000.

Various. "USS Ward Crew: In Their Own Words." USS Ward DD-139. SpecWarNet, 16 Nov. 2002. Web. 10 Jun. 2010. <>

Wilford, T. "Decoding Pearl Harbor: USN Cryptanalysis and the Challenge of JN-25B in 1941." The Northern Mariner. 1 Jan. 2002, Volume 12, Number 1: 18.

Reference this article:
Dunning, B. "Attack on Pearl Harbor." Skeptoid Podcast. Skeptoid Media, 22 Jun 2010. Web. 13 Oct 2015. <>


10 most recent comments | Show all 118 comments

Ok, given that rhetoric takes ahold as some basis for argument amongst the conspiracists the facts remain unassailed.

Should the skeptoid commenters who take a conspiratorial approach to their thinking, would they consider what was going on as Quincy Adams Wagstaff was himself portrayed as saying his basis for argument.

The USA was carrying out an economic war of bastardry against Japan in the japanese view. The Japanese attacked the US fleet at Pearl Harbour after a very good intelligence isolation war. The current view forgets comms were easily corrupted when technology was just becoming useful for modern warfare. (note Rogue waves were just being investigated about this time!).

This alone provides for refutation of the notion that the USA knew what was going to happen. There was no sweet deal, there was only the ridiculous final turn that the axis forces initiated in planning for the attack.

Personally, I'd call it craven that the US waited (once again) until a good reason for entering a war (they were attacked by a force that was superior in every way, materiele and planning).

The US had plenty of reasons to go to war and should have much earlier rather than letting it escalate.

Pearl Harbour showed a remarkable lack of planning on the part of the US and a rehash of shock attack the Japanese used sparingly on weaker-weakend nations.

Conspiacism on this matter is, as always, a fail. At least Quincy Adams Wagstaff and Mr horse were a bit more honest..

Magnificent Devon, Ich bin ein Berliner?, Pho's diner, greenacres by the sea, Oz
November 14, 2013 9:33pm

The above poster has provided nothing resembling any convincing argument against my mainstream-proven facts that support my assertions that the Pearl Harbour attack was not a surprise to Roosevelt and senior naval staff (at least), and was encouraged to take place in order to quash a considerable public opposition, and provide manpower for a full war.

Whether the above poster calls such a strategy craven or not, it has been a tried and true American tactic for entering wars since as well, such as Vietnam and I suspect the Middle East currently, and continues to suck enough of the public in to provide majority support, and the manpower to conduct said wars.

It was a prime strategy unanimously approved by US general staff for Northwoods, whether actually carried out or not, and like "pre-WW2" skirmishing in the Atlantic by US forces, the military operations conducted pre-Vietnam war (pre-Gulf of Tonkin incident) show that such military planning is a stock-in-trade US method for such wars, if not providing conclusive proof.

The above poster is correct in one of his phrases "the facts remain unassailed".

I have provided the facts as they occurred from mainstream sources for my assertions, and the above poster's references to a 1932 Marx Brothers comedy film serve only as yet another attempted example of confusion, in order to escape confronting my irrefutable evidence of Roosevelt knowing exactly what he was doing regarding the Pacific Fleet deployment in Pearl Harbour.

Macky, Auckland
November 15, 2013 2:44pm

I see nothing in this debate that can't be chalked up to one of the following factors:

-Underestimating Japanese capabilities and skill
-Poor communication
-Inter-service squabbling
-Poor doctrine
-Calcified leadership
-Technological deficiency
-Misplaced priorities
-Overstretched military forces
-Poor training
-Not knowing how to disseminate and interpret information

Mike R., Pasadena, CA
December 8, 2013 1:34pm

In that case Mike, your position is firmly that Roosevelt got an awful surprise when the US Pacific Fleet berthed in Pearl Harbour was attacked ?

That Roosevelt didn't see it coming despite being warned 10 months earlier by his then Pacific Fleet Commander Richardson against ordering the fleet berthed in Pearl Harbour, because Richardson, the top US Navy authority on Japanese naval warfare asserted that Pearl Harbour would be the logical first place for any IJN attack, should the fleet be berthed there ?

That Roosevelt, with all his navy experience, and his attendance at US Navy exercises nearby Pearl Harbour in 1938, where Pearl Harbour was also successfully mock attacked (again), managed to somehow forget everything he knew about things navy over several decades, everything he had been told only 10 months before, and everything he himself had attended by way of US naval exercises (which according to Nimitz and other authorities always had Japan as the anticipated opponent), and got such an oh so dreadful shock when the naughty treacherous Japanese caught Pearl Harbour with its pants well and truly down ?

While some of what you've posted is undoubtedly part of the story, the prime reason for Roosevelt ordering the berthing of the Pacific Fleet in Pearl Harbour was obvious the very next day after the attack, when the over 50% opposition to all-out war evaporated within the American public, and the booths were overflowing with said public signing up for a full war.

Macky, Auckland
December 8, 2013 3:16pm

Macky, what courses of action had Roosevelt NOT been warned against by various military and political officials?

Brian Dunning, Laguna Niguel, CA
December 8, 2013 5:08pm

With respect Brian, I do not see the point of your question.

Any number of scenarios could well have been put to Roosevelt as serious possibilities, but the utterly inescapable fact is that he was vigorously warned against ordering the fleet to PH by the Pacific Fleet commander, which Roosevelt not only ignored, but sacked said fleet commander into the bargain for having the courage of his convictions.
In other words James O. Richardson stuck to his guns and suffered demotion because of it.

The comfortable American (and their allies I might add) story so drummed into our minds that America went to war because it was attacked is actually true to some degree.

But the ordering of the Pacific Fleet to Pearl Harbour was a clever ploy by a very astute politician with much naval experience, to foment war by providing an irresistible target for the IJN, and I have provided much mainstream evidence to counter the "skeptical" position, fraught with confirmation bias, that Roosevelt got such a shock when the very thing he had been warned about only 10 months previous by top naval staff, in fact took place.

If that piece of American pseudo-history happens to be true, then the only conclusion we can come to is that Roosevelt was an incompetent imbecile, forgetting his own naval experience, top naval staff warnings, and the results of successful mock attacks of PH during naval exercises that targeted Japan over a decade.

And we all know that that is certainly what he was not.

Macky, Auckland
December 8, 2013 11:49pm

This website was pretty decent and i learnt a lot

xoxo gossip goat

Allysha Stephenly, Mebourne NSW
March 19, 2014 3:27pm

"higashi no kaze ame" 東風の雨, the now famous "Winds Execute" message was not dealt with here. Even then, they did not tell anyone that mattered, they just entered it in the log...I met the Navy Warrant Officer that as a rate, recorded the entry in the log at "Hypo" in Hawaii. I was amazed that someone fluent in Japanese was paid so little in 1941!! He was just an ordinary Seaman, not even a Petty Officer!!!

Dale Martin, Birmingham AL
April 22, 2014 10:00am

There are many aspects leading up to, and including the Pearl Harbor attack.

Mike R. detailed quite a few :-
-Underestimating Japanese capabilities and skill
-Poor communication
-Inter-service squabbling
-Poor doctrine
-Calcified leadership
-Technological deficiency
-Misplaced priorities
-Overstretched military forces
-Poor training
-Not knowing how to disseminate and interpret information

While all of them no doubt played their part in the overall scenario, along with the speculations about how much of the JN25 code etc was known, they all serve as diversionary arguments from the one simple fact that it was Roosevelt who ordered the US Pacific Fleet to berth in Pearl Harbour.

It was Roosevelt that removed the only significant resistance to his order ( James O. Richardson ).

It was Roosevelt who attended naval exercises that targeted Japan, and where successful mock attacks on Pearl Harbour were staged.

It was Roosevelt that had decades of experience in things navy, and maintained that through his career.

It was Roosevelt that faced a majority of US public that were against a full war.

He promised that public he would never send their sons to war unless America was attacked first.

Roosevelt himself provided that opportunity for the IJN, having already squeezed oil exports to Japan.

Roosevelt couldn't have been surprised by the IJN attack.

He instigated America's full involvement in WW2 by ordering a massive naval decoy to Pearl Harbour.

Macky, Auckland
May 16, 2014 6:37pm

I must commend Skeptoid for providing a forum for such a spirited, if not always logical, debate. The tragedy of Pearl Harbor has led me to a great deal of reading, fiction and non-fiction for 50 years. I was fortunate as a high school Navy brat in the mid-60s to view first-hand remnants of the attack, down to the bullet holes that pockmarked the base.

I subscribe to the belief that, nine times out of ten, the simplest, most obvious answer is the correct. But we love our conspiracy theories.

Question - were our three carriers at sea unescorted? Does anyone know? Especially since each carrier operated separately, even in peacetime it would have been prudent to provide each with at least two or three destroyers.

Thanks in advance!

Tom Duncan, Memphis, TN
September 9, 2015 12:34pm

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