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Here is the challenge: with any POD as far back as 1849, make the 20th century US into the kind of country the Japanese prayed it would be when they attacked.

That is a country that is not unshakably bent on revenge as long as it takes but instead is prepared to write off some losses and peace out leaving the attacker to claim victory.

Here are the conditions:

Any PoD after 1849
The attack on the US may happen any time in the20th century.
The US does not need to be conquered, it just needs to peace out, conceding a national interest or peripheral territory to the enemy, or even just failing to exact revenge.
This defeat cannot be brought on by any of the 4 horsemen of the apocalypse, or vast natural or supernatural catastrophe. It can come about through major social, political or economic catastrophe or weakness.
It can be any enemy.

With such a wide range of choice, no matter how difficult this challenge should not require ASB assistance.

As the Japanese found when they fought China in 1890s and Russia in 1904, sometimes the bigger country, with greater size, resources an national capacity, just cannot get its act together to win.

I have no doubt the Chinese and Russians were hopping mad when Japan sneak attacked them. But that rage was not enough to overcome the challenges sufficiently to win. Perhaps the key is having a citizenry hopping mad about a million other things in addition to the foreign surprise attack.
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