40

Japan successfully wiped out America's defenses at Pearl Harbor, and they knew they were going to before they set out, so why didn't they take some paratroopers with them to seize the harbor from the US? This would have had even more of an impact than just blowing stuff up.

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    They never had the chance. It's one thing to blow things up from air; it's quite another to land marines and actually hold the islands. – Semaphore Jan 23 '18 at 15:59
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    I'd question that the Japanese attack "wiped out" the defenses of the Hawai'ian Islands. True, they penetrated the defenses at Pearl Harbor, but that was in large part due to the element of surprise. Remember that the entire attack took just two hours. I would think that, given a few hours to react and organize, the substantial US force remaining could have held off any invasion. – jamesqf Jan 23 '18 at 19:40
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    @jamesqf What the attack did was inflict major damage on the fleet. Heck, they missed the oil supplies. And the carriers were at sea. There's plenty wrong with the basic assumptions imbedded in the question. – KorvinStarmast Jan 23 '18 at 21:50
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    Where did you get the impression that the defenses were wiped out? – user27190 Jan 24 '18 at 1:47
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    I'm voting to close this question as off-topic because it makes a false premise: that the Japanese had a "chance" to take Pearl Harbor inexpensively. – Pieter Geerkens Jan 25 '18 at 4:32
77

There are two simple reasons they did not, besides "they couldn't"

The "they couldn't" is underscored by the fact that their longest range transport planes had ranges (one way) of at most 3300 km (about 1700 NM) so even on a one way trip they can't reach Hawaii. But the idea is dead in the water for a number of very basic reasons, the two primary ones being Strategic and Logistic.

Objectives

The Japanese planned to occupy the Philippines as part of their plan for a "Greater East Asia War" in which their Southern Expeditionary Army Group seized sources of raw materials in Malaya and the Netherlands East Indies while the Combined Fleet neutralized the United States Pacific Fleet.

In military terms, the attack on Pearl Harbor was not the main effort. It was a supporting effort to the main effort, which was in the Philippines and points east in the Dutch East Indies.

A point on fundamental military doctrine: you weight1 the main effort

Strategic

The whole point of attacking and neutralizing the US fleet at Pearl Harbor was to buy time to take over parts of Southeast Asia: the reason to do that was to consolidate their natural resource access requirements. Taking the Philippines was the more critical task in that strategy, since that would eliminate American interference with getting oil and other materials from southeast Asia. Japan successfully invaded and occupied the Philippines, and removed the Americans from that geo-strategic position. The attack on the Pearl Harbor was synchronized pretty well with the attack on the Philippines .

Logistic

The logistic problems to any follow up parachute assault after the Pearl Harbor attack (if it succeeded) were numerous. Two prime ones are:

  1. Their planes could not fly far enough to drop a division on Pearl Harbor, from Japan. They'd have had to build forward air bases to make such an airborne attack even possible. As they didn't have any territory on which to build forward bases, they'd have had to invade and take islands to build them. (Even having taken Midway before Pearl Harbor, they'd have had to modify those transport aircraft to get more range out of them ... 1300 NM from Midway to Pearl, 2600 NM round trip).

    This building forward bases ahead of time from which to stage the parachute division (established in 1938) would have ruined the surprise attack on Pearl Harbor (strategic surprise was an element of the achieved tactical surprise).

  2. The other problem is extended supply lines:

    They'd then have to support a light division across thousands of miles of ocean, but their main effort was in the Philippines. Militarily, it would have been a lousy idea to drop a division (if they even could) and then try to take / hold Pearl Harbor.

The subsequent attacks on Wake Island and Midway were aimed at extending their basing ability to provide land based air, once the "we'll knock the American fleet out and they'll stay out of our way" strategy failed. Those two campaigns were not any good for the Pearl harbor attack, in a temporal sense.

A third reason: the Japanese had observed the European War

The attack on Pearl Harbor was informed by, and gained support in the Imperial General Staff, the successful attack on Taranto by British carrier based aircraft in November of 1940.

Admiral Yamamoto ordered the Japanese naval attachés in London and Rome to make detailed studies of the Taranto raid

Given the cost and near failure of the paratroop attacks on Crete, from nearby Greece, it is doubtful that the Japanese would conclude from that operation that an airborne assault across many thousands of miles of ocean would be a good idea. (Riffing off a point made by @TomAu in his answer). A further example of the risks of an airborne assault was the German airborne assault on the Hague. This was an attack against a well defended position which caused significant losses in troop transport assets. (@BasJansen, thank you). If you look at how spread out the Japanese areas of control and occupation were, risking major losses to their air transport assets would be another argument against this high risk operation if it were suggested to the Imperial General Staff.


1 Then the weight of effort (Schwerpunkt) would be in that area. The second key element was concentration at the weight of effort (Schwerpunktbildung).

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    WRT building forward air bases, are there even any islands within a practical distance? IIRC, the nearest is Midway, at about 1300 miles. (Johnston Atoll is closer, but doesn't seen large enough to support a forward base.( – jamesqf Jan 23 '18 at 19:32
  • @jamesqf I added a note, good point. Had they wanted to do this, I do not put it past the Japanese to have modified their transport aircraft to get more range out of them (they had some pretty ingenious innovations) but as this is a bad idea to start with that was not likely to happen. – KorvinStarmast Jan 23 '18 at 19:49
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    I would argue that the failed paratroop assault of Germany against the Hague is a better example than the attack on Crete, because the attack against the Hague was a paratroop assault against a properly defended/fortified position where the germans suffered significant losses to their aerial transport branche (whatever that might be called). – Bas Jansen Jan 24 '18 at 13:00
  • @BasJansen Interesting parallel, however the assault on Crete as an "across the water" operation as the proposed airborne assault on Hawaii was ... both offer lessons learned. I can slide in a note on the Hague airborne assault as well. – KorvinStarmast Jan 24 '18 at 13:33
  • @KorvinStarmast Fair point and just wanted to throw it up there as many people don't know of that attack (while to my knowledge it was the first paratroop assault in history against a defended position). – Bas Jansen Jan 24 '18 at 14:49
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The specific scenario of using paratroopers is a nonstarter. In addition to @KorvinStarmast's answer on why it's infeasible, Japan actually only had about 1,500 paratroopers. There simply wasn't enough of them to actually do anything, even if they could be transported to Hawaii.

(For the rest of the post I'm treating "take Pearl Harbor" as taking Hawaii. Taking the harbor by itself is rather meaningless, since it's impossible to hold on to without also taking the rest of the island and Hawaii. That said, the US Army had garrisons near the harbor precisely to defend it anyway.)


The reality was that Japan never had any chance even if they wanted to.

The US military actually took the defense of Oahu, where Pearl Harbor is located, very seriously. A few months before the attack, Marshall went as far as boasting to President Roosevelt that the island was "the strongest fortress in the world". Accurate or not, by 1941, Hawaii was defended by a sizable army numbering over 42,000.

Hence, the premise of the question is not very accurate. The Japanese strikes inflicted a great deal of damage, especially to the navy, but Hawaii's defenses were far from "wiped out". In fact, of the planes Japan lost in the attack, 20 out of 29 planes were shot down during the second strike.

The island of Oahu, due to its fortification, its garrison and its physical characteristics, is believed to be the strongest fortress in the world.

Boer, Peter F. Opportunity: The Hidden Side of Wealth: The Hidden Side of Wealth. Xlibris, Corp., 2010.


In the year preceding the Pearl Harbor attack, the Army's officer and enlisted strength in the Hawaiian Department grew from 28,798 to 43,177, and Hawaii remained the largest of the overseas garrisons.

Conn, Stetson, and Byron Fairchild. United States Army in World War II: The Western Hemisphere. Conn, Engelman, & Fairchild, 1960.

This is clearly not some basic security that a surprise airborne assault could overwhelm. It's one thing to bomb such a force. It's quite another to dislocate it from an island - as the rest of the Pacific Campaign would later demonstrate. A multi-division invasion force would have to be mustered and ferried across the ocean, and supplied indefinitely.And that was simply strategically and logistically infeasible.

To put things in perspective, the attack on Pearl Harbor was only one part of an extensive Japanese campaign throughout Southeast Asia. At very nearly the same time, the Japanese Army landed in the Philippines with some 43,000 troops, attacked British Malay with about 35,000, and invaded Dutch East Indies with around 55,000. All of these locations were far closer to Japanese bases than Hawaii. Yet, these campaigns still stretched Japanese logistics beyond its limits.

Japanese logistics were abysmal. Several times in 1942, Japanese operations in Burma and elsewhere were built around limitations of supply, and offensives might have been halted were they not able to use captured Allied supplies and vehicles; for instance, during the battle for New Guinea, Japanese troops were ordered to capture supplies post-haste in order for future offensives to be possible

Anglim, Simon. Orde Wingate and the British Army, 1922-1944. Routledge, 2015

An invasion of Hawaii would require a force on the same order of magnitude as the aforementioned ones, but at a considerably higher expense due to the distance involved. Japan had entered the war with a 35% hole in its shipping needs, which were previously filled by Allied merchant marines. To supply an additional force to attack Hawaii, even assuming the necessary manpower could be found, was impossible without giving up on their other plans in South East Asia. Which brings me to the next point.


Realistically, Hawaii was strategically useless to Japan, so they didn't want to anyway.

The entire reason Japan entered the Pacific War was to take the resources of South East Asia, which had been denied to it by the US embargo. What resources did Hawaii have? It was a massive detour for no practical gains, not even worth the effort of supplying a garrison. The only reason they attacked Hawaii at all, was to knock out the US Pacific Fleet in order to prevent it from interfering in Japan's southern operations.

Japan faced several shortages, but the most pressing one was oil.

As the embargo took hold, the Japanese navy alone was consuming 400 tons of oil per hour and was becoming desperate as supplies dwindled by 28,000 tons per day. The Japanese had no alternative but to capitulate to the embargo and negotiate a humiliating deal or to seize the rich and weakly defended oil fields in Sumatra and Borneo, the only ones accessible within their military capabilities.

Reyes, Major Blanca. Waking the Sleeping Giant at Pearl Harbor: A Case for Intelligence and Operations Fusion. Pickle Partners Publishing, 2015.

At the time Japan's oil reserves was only some 43 million barrels of oil. The daily consumption of 28,000 tons is just over 190,000 barrels - in other words, the stockpile was only good for less than eight months. Securing the Dutch oil fields was thus the top priority, and the Japanese military carefully planned their operations to open such a supply line as quickly as possible.

enter image description here Japanese advances up to 1942. See how out of the way Hawaii is from the main objective, Dutch East indies.

Even if it was technically possible for Japan to muster enough forces to take Hawaii at the start of the war, there was no oil in Hawaii. In other words, it wouldn't accomplish anything other than to cripple Japan when the oil runs out soon afterwards.

39

Japan successfully wiped out America's defenses at Pearl Harbor,

The basic premise of your question is faulty: the American defenses weren't wiped out. Look at the list of what the Japanese hit (from Wikipedia):

  • 4 battleships sunk
  • 4 battleships damaged
  • 2 other ships sunk
  • 3 cruisers damaged
  • 3 destroyers damaged
  • 3 other ships damaged
  • 188 aircraft destroyed
  • 159 aircraft damaged

Note what that list doesn't mention? Two dozen destroyers. Minelayers. Torpedo boats. Coastal artillery. Antiaircraft guns. The 40,000-strong Army garrison. Four battalions of Marines. The attack on Pearl Harbor didn't wipe out America's defenses, it wiped out the offensive force. A paratrooper drop, or even an all-out amphibious assault, would have been defeated almost immediately.

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    Don't forget ~400,000 Hawaiian civilians to pacify. – ceejayoz Jan 24 '18 at 15:44
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    It didn't even wipe out the offensive naval force, just damaged it - as later events demonstrated. – jamesqf Jan 24 '18 at 19:27
  • I like this answer. However, the garrison in the Phillipines was even larger, and the Japanese invaded there successfully. So the challenge must have been more than sheer numbers. – T.E.D. Jan 25 '18 at 20:08
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    @T.E.D., the Philippine garrison was only about 30,000 regulars, plus around a hundred thousand poorly-trained, poorly-equipped recruits. Additionally, they had maybe a quarter the artillery of Oahu, half as many ships, fewer static fortifications, and were at the wrong end of a month-long supply route. – Mark Jan 26 '18 at 0:28
  • @Mark: Also, the Phillipines were at the time an American colony that wasn't entirely happy about being American. (See e.g. Moro Rebellion.) – jamesqf Jan 27 '18 at 19:47
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One answer to this question lies in President Roosevelt's "day of infamy" speech.

"Yesterday the Japanese Government also launched an attack against Malaya.
Last night, Japanese forces attacked Hong Kong.
Last night, Japanese forces attacked Guam.
Last night, Japanese forces attacked the Philippine Islands.
Last night, Japanese forces attacked Wake Island.
And this morning, the Japanese attacked Midway Island."

The Japanese were engaged all over the Pacific, and spread very thin. Pearl Harbor was the farthest away of their targets, and therefore the lowest priority for occupation. The Japanese might have attempted Hawaii after capturing all the other targets above, to extend their base, but not before. Their goal in December 1941 was to neutralize Pearl Harbor, specifically its fleet, not to occupy it.

Regarding "paratroopers," Hawaii was a lot farther from the Japanese bases than Crete was from say, Greece. The "paradrop" on Crete barely succeeded, suggesting that a similar attempt on Hawaii, without the ability to reinforce and resupply the invaders, would have failed.

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    @LangLangC: I answered "paratroopers" because it was in the original question, thereby addressing the OP's specific concern.But the underlying issue was reinforcement/resupply, which would be common to "all" means of attack. – Tom Au Jan 23 '18 at 18:47
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Invasion of Hawaii after a three staged air attack on Pearl Harbor was discussed and rejected even though the Japanese realized Hawaii was important to both countries.

This source answers the question well. Not mentioned above was the competition between the Army and Navy and the difficulty in coordinating between the two. This played a significant role in the decision on Hawaii.

Genda

Planner, Commander Minoru Genda who saw Hawaii as vital for American operations against Japan after war began, believed Japan must follow any attack on Pearl Harbor with an invasion of Hawaii or risk losing the war. He viewed Hawaii as a base to threaten the west coast of North America, and perhaps as a negotiating tool for ending the war. He believed, following a successful air attack, 10,000-15,000 men could capture Hawaii, and saw the operation as a precursor or alternative to a Japanese invasion of the Philippines. In September 1941, Commander Yasuji Watanabe of the Combined Fleet staff estimated two divisions (30,000 men) and 80 ships, in addition to the carrier strike force, could capture the islands. He identified two possible landing sites, near Haleiwa and Kaneohe Bay, and proposed both be used in an operation that would require up to four weeks with Japanese air superiority.

Although this idea gained some support, it was soon dismissed for several reasons:

  • Japan's ground forces, logistics, and resources were already fully committed, not only to the Second Sino-Japanese War but also for offensives in Southeast Asia that were planned to occur almost simultaneously with the Pearl Harbor attack.
  • The Imperial Japanese Army (IJA) insisted it needed to focus on operations in China and Southeast Asia, and refused to provide substantial support elsewhere. Because of a lack of cooperation between the services, the IJN never discussed the Hawaiian invasion proposal with the IJA.
  • Most of the senior officers of the Combined Fleet, in particular Admiral Nagano, believed an invasion of Hawaii was too risky.

Quoted material is from Wikpedia: Events leading to the attack on Pearl Harbor: Concept of a Japanese invasion of Hawaii

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    I'm.. really not sure why the whole first quote block got linked to the image above. Also, since it's a quotation, mention the source, please? – Andrew T. Jan 24 '18 at 6:33
  • I've edited to address @AndrewT's comment - I hope that my edits help rather than hinder, but any errors are mine, not JMS'. – Mark C. Wallace Jan 25 '18 at 15:00
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As outlined above occupation of Hawaii was never possible. I would like to outline why:

  • In the literature there is an agreement that the attack on Pearl Harbor was to remove the US fleet from stopping the conquest of the Southern Resource Area which was the actual casus belli.

  • The IJA (Army) had no part in planning the attack on Pearl Harbor and was instead moving all forces not needed in China to invade Thailand, DEI and the Philippines. The infantry available to the IJA was limited to SNLF which would not be enough especially since it was already detailed for other operations.

As a counter-factual: it's possible that Japan could have actually conquered the "Southern Resource Area" without bringing the US into the war.

  • Best answer right here, in that it succinctly goes into both what their actual objectives were and what resources they had available at the time to work with. – T.E.D. Jan 25 '18 at 20:12
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Another factor to consider:

The Pearl Harbor attack was dangerous for Japan. They committed the bulk of their carrier forces, six carriers, to the attack, with over 1000 miles to travel before the fleet could be back under land based air cover. They ran the strong risk of being discovered while approaching Hawaii, and could have been facing the US fleet at sea. Any ships that were severely damaged at Pearl Harbor would probably have been lost on the long return voyage. Had the Japanese fleet run into effective opposition, they could have seen their offensive power severely limited.

Which is exactly what happened at Midway six months later, when they lost four carriers. Japan never captured any more territory through naval action after Midway. After the costly naval actions around Guadalcanal, whose losses Japan couldn't replace but the US forces could, the IJN ceased to pose a serious offensive threat. That also could have been the result of a Pearl Harbor attack gone wrong.

Pearl Harbor was a long way from friendly waters and support, much further than Japan had ever staged a major offensive action. Keeping a garrison at Hawaii provisioned with war consumables: weapons and ammunition, would have been impossible, even before US submarines wreaked havoc on Japanese shipping. So while Japan could possibly have taken the Hawaii islands, had they brought most of their marine forces with them, they couldn't have held those islands for very long, and they would have lost a large number of highly trained Imperial Marines in the process.

And even taking Hawaii would be in doubt: Not long after the Pearl Harbor attack, a relatively small number of determined US Marines on Wake Island put up a very spirited defense, driving off the first Japanese landing attempt, before a second, more heavily supported attack finally succeeded.

When the first Pearl Harbor attack wave met with great success, Nagumo promptly secured the aircraft and ran for friendly waters, to avoid damage from an expected counterattack. That is why the huge oil reserves at Pearl were not destroyed - the second attack wave was never carried out, due to fears of heavy damage to the fleet, at such a great distance from Japanese controlled waters.

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    Actually, it was the third wave that was never carried out: the first hit battleships and airfields, while the second hit airfields and cruisers (both were tasked with hitting aircraft carriers, but the carriers weren't there). A third wave would have risked substantial loss of aircraft, due both to rapidly-improving American antiaircraft fire and to crashes during the resulting nighttime carrier landings. – Mark Jan 26 '18 at 0:41
  • Instead of Wake Island, a better illustration might be the preliminary defense of Bataan. The initial Japanese assault failed (catastrophically so in the Battle of the Points). They needed to bring in substantial reinforcements and wait two months for the defenders to starve before they were able to successfully capture Bataan. If the original hypothetical Japanese invasion would have failed then it would be the American defenders who would be able to bring in reinforcements and the Japanese invaders who would be running out of supplies. – John Coleman Jan 27 '18 at 13:36

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