If Japan was still a semi-feudal Shogun-style country I would worry.
Not really, but I see your intent. It's because the samurais were repressed and done away with, that Japan was able to rise as an industrial power and challenge the Western powers. The warrior spirit lived on, despite swords being taken from the samurai. Their backs were against the wall when the USA blocked their access to resources as they sought to bring Asia under Asian control (in their minds). War was inevitable then. As for now, it's China that wants to bring Asia under Asian control, and war may again be inevitable.
Waging war against the US was the smartest thing Japan did in the 20th century — look how they improved their standard of living.
That they got nuked in the process is merely collateral damage.