A study I did over 50 years ago laid a solid foundation for the premise that FDR manipulated the Japanese to commit the first step.
We had the Purple machine which deciphered the Japanese code. The furthest west that one of those machines was placed was Hawaii. None of the American installations further west had one. FDR wanted in the war for several reasons but did not want to be seen as the aggressor.

Goes further back. We should never got involved in WW1. Or done any trade with either side. A lot of our problems go back to so called foreign adventures in South America,Cuba, Philippines and China.

Re: “It may not have been a popular opinion during the life of my one-time seminary professor, Dr. C. Gregg Singer, but he was convinced that the Pacific theater of the war was a totally unnecessary and wasteful mistake, and whatever differences we had with Japan could have been solved peacefully. Furthermore, he was convinced that the embargo was the catalyst for the attack on Pearl Harbor.” There is no need for “conspiracy theories” regarding the attack upon Pearl Harbor, or the fact that President Roosevelt and his senior advisors knew that war with Japan was coming in the days, months and even years prior to the attack. It is a matter of historical record that relations between the two nations had been deteriorating for many years – at first slowly and imperceptibly – and then more-rapidly and obviously as December 1941 approached. Although relations between the two nations were somewhat normal and cordial in the decades prior to the war – Japan had been on the Allied side during WWI in fact – there were also many sources of tension, disagreement and ultimately anger and alienation. It is not possible to understand the Great Pacific War, as the Japanese call WWII in the Pacific and China-Burma-India theaters – without understanding Japan herself since the Meiji Restoration of 1868. Japan had been, prior to her “opening” by the U.S. and the West in 1853, a medieval and largely feudal society. In the span of a remarkably short period of three decades from 1870 forward, she transformed herself into a modern, first-world industrial & technological power. As a feat of rapid modernization, it was almost unprecedented in history up to that time. It was a stupendous achievement, really, one not fully-appreciated in the West at the time. Japan’s “coming out party,” geopolitically-speaking was her stunning victory in the Russo-Japanese War of 1905, whose culmination saw the great Admiral Heihachiro Togo – the Japanese “Horatio Nelson” – soundly defeat the naval forces of Imperial Russia at the Battle of Tsushima. Having successfully modernized, Japan wanted to become a world power, a great imperial power – in emulation of the already-established powers such as Great Britain, France, Germany, Italy and the United States. Seeing the extent of the imperial possessions and colonies of these various nations in Africa, Asia and elsewhere, Japan sought to emulate their example. Japan had already intervened in Korea by 1890, and formally occupied the peninsula from 1910 until the end of the Second World War in 1945. She also pushed into mainland China as early as the 1910s and 1920s, exploiting the internal unrest then occurring in that nation. And like the European imperial powers and the U.S., Japan had won the right to station her troops on Chinese soil in the aftermath of the Boxer Rebellion of 1900, whose treaty peace terms had imposed these terms on her militarily-defeated empress. So, for forty years or so, all of the nations maintained military forces inside China. This was… Read more »

@ Herschel

Re: “Even now, I expect [and hope] that Japan amends its constitution to allow a more robust military. They’re going to need it against China.”

The Japanese have been concerned for some time now about the resurgence of the People’s Republic of China. Quite naturally, since they lie in such close proximity to the Asian mainland. And also, because memories are rather long in that part of the world.

For some years now, going back more than a decade, Japanese leaders have debated whether or not to renounce all or part of her post-war constitution, which prohibits rearming of the Japanese military except for strictly defensive purposes. Very quietly and discreetly, Japan has rearmed herself – and this has been done with the tacit approval of the U.S. Japan has also participated in a greater number of joint military training exercises with the U.S. and her other allies in the region.

The Japanese are a formidable opponent, and Beijing knows it. Consequently, Tokyo is an important check upon Beijing’s ambitions and bellicosity.

The million-dollar question remains: Do the Japanese have the atomic bomb? Either one or more of their own design, or purchased from the U.S.? Although they would be very unlikely to admit to such for public attribution, I believe the answer to be in the affirmative. Or, if they do not have them, they have the means and ability to manufacture them quickly. Including fissile material.

From some acquaintances that once upon a time worked for some Beltway Bandits, i.e “Think Tanks”, the consensus is that Japan is only a few turns of a screwdriver away from having a decent little collection of nuclear and thermonuclear toys. Not literal screwdrivers, of course, but that it would take very little time to get the devices operational.
I’ve done some military simulations on the side, and did one last year where Japan intervenes when Taiwan gets invaded. China drops a few nukes on Japan, and then, all hell breaks loose in China. At the end of the game, China no longer had an overpopulation problem, and their major cities and ports all glowed in even daylight.
Regarding Georgiaboy’s question, I suspect(but have no evidence) that Japan has developed their own devices, with a little help from US and British experts. We had Japanese citizens in American engineering colleges during the 70s, and these students were very…intense. While I was playing Dungeons and Dragons, getting sued by Gary Gygax over copyright issues, and such, these people were learning about the peaceful use of nuclear materials. Some of the professors worked on less peaceful uses of nuclear material during the 50s thru the early 70s. One of these guys had a really interesting patch collection, and displayed it in his office. He NEVER explained what most of the patches were for; only the ones that were common knowledge.
China is being very foolish in threatening to use nuclear weapons on Japan, or even South Korea. I have no doubt that the South Koreans have their own little shop of radioactive horrors, although I doubt they have more than a dozen or so. Just enough to deter the crazies to their north, keep Japanese warplanners awake at night, and give Chairman Xi some first class nightmares.

Japan, and South Korea have to be observing what is happening in America and they are certainly making alternative plans. They must know that America is no longer a reliable ally.