According to Wikipedia, Japan attacked Pearl Harbour to prevent the US Pacific Fleet from interfering with its actions in South-East Asia.

However, Noam Chomsky, referring to Michael Sherry's The Rise of American Air-Power, relates that:

The Japanese knew the B-17 flying fortresses were coming off the production lines of Boeing and could read in the American press that planes capable of burning down Tokyo, "a city of rice-paper and wood houses". A November 1940 plan to "bomb Tokyo and other big cities" was enthusiatically recieved by the Secretary of State, Cordell Hull. FDR was "simply delighted" at the idea - described graphically by its mastermind, air force general Claire Lee Chennault: to "burn out the industrial heart of the Empire with fire-bomb attacks on the teeming bamboo anthills of Honshu & Kyushu."

By July 1941, the air-corps was ferrying B-17s to the Far East for this purpose, moving half of all the big bombers from the Atlantic sea-lanes to this region. If needed, the planes would be used "to set the paper cities of Japan on fire," General George C. Marshall explained in a confidential press briefing on 15th November 1941, adding "there won't be any hesitation in bombing civilians." Four days later, New York Times senior correspondant, Arthur Krock, presumanly basing himself on Marshall's briefing, reported US plans to bomb Japan from Siberian and Phillipine bases, to which the air force was rushing incendiary bombs intended for civilian targets. Washington knew from decoded messages that Japan was aware of the dispatch of B-17s.

The attack by Japan on Pearl Harbour was on the 7th December 1941.

Hence the question:

Q. Why was the the USA planning to attack Japan before the Japanese attack on Pearl Harbour?

  • 14
    I think this would be better placed on History.se
    – Jontia
    Mar 27, 2021 at 13:51
  • 3
    check out an answer on SE.History, where this question belonged in the first place. Mar 27, 2021 at 20:07
  • 1
    If you're interested in reading up a modern interpretation of why Japan went to war, Eri Hotta's 1941 countdown to infamy, based on Japanese sources, seems to be the hot book of the moment, like Shattered Sword is to Midway. Here's a guest article on Guardian by the author re Pearl Harbor. Mar 28, 2021 at 19:55
  • having broken their codes, we knew they were going to attack us and our territories.
    – dandavis
    Mar 31, 2021 at 23:19
  • Do you count a navalcblockade as an attack?
    – Jasen
    Apr 4, 2021 at 6:25

1 Answer 1


Halfway compentent military staffs have more plans than they ever expect to use. Until 1939 or even later, the United States had a plan for war against Canada and the UK. Relations between the US and Japan were much worse than those between the US and Canada, so of course American planners had plenty of plans what to do if it ever came to a war against Japan.

In the end War Plan Orange was not executed as it was written, but it is much easier to re-write an existing plan on the fly than to start from scratch.

One might consider it a somewhat impolite act to have war plans against countries one is not actively fighting, but that's why they are usually kept secret. Currently the US has war plans dealing with North Korea, Iran, and many others.

  • 2
    Actually, the link that you have for a 'war plan against Canada & the UK' points out that this is a training exercise primarily to help mid-level officers inexperienced with the actually planning of logistics for a major war to plan for one. There is no indication that this was a war-plan in operation. Whilst, in the post Sherry pounts out that the USA was "by July 1941, ferrying B-17s to the Far East for this purpose, moving half of all the big bombers from the Atlantic sea-lanes to this region" and 'this purpose' is the previously mentioned war-plan of air-force general (not a ... Mar 27, 2021 at 15:30
  • ... mid-level officer) Claire Lee Chennault which began in November 1940, to "burn out the industrial heart of [Japan's] empire with fire-bomb attacks on the teeming bamboo anthills of Honshu & Kyushu". This was no training exercise, but the exercise of real raw military power. Mar 27, 2021 at 15:34
  • @MoziburUllah, in that case, why stop planning in 1939? They had to train more staff officers, not fewer. It was a low probability, low priority plan but it was a plan. Also consider Orange-Red, and the traditional alliance of the RN and the IJN earlier in the century.
    – o.m.
    Mar 27, 2021 at 15:41
  • 2
    A.J Taylor made this point when discussing why the Germans had plans for invading France prior to WW1. He said, as you do, that "it is the function of general staffs to plan for wars."
    – James K
    Mar 27, 2021 at 17:12

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