US alternate history in Second World War

If Japan hadn’t attacked Pearl Harbor or the Philippines, and had never throughout the course of its war in the Pacific and in China, attacked any U.S. ship, base, civilian or military property, and had not killed any U.S. soldiers or civilians, but did invade and conquer the Indonesian archipelago, New Guinea, Southeast Asia, and selectively “skipped over” the Philippines and Hawaii, and neither did any of the Axis powers do anything of the above that Japan did not do, could Roosevelt ever had successfully asked Congress for a declaration of war?

If the U.S. had not entered the Second World War, and it had been fought to a victorious conclusion by the British Empire and the Soviet Union, although not necessarily an unconditional surrender, but a decisive military victory more conclusive than the victory won by the Triple Entente in the First World War but less so than unconditional surrender, would:
-America have developed an atom bomb, or have completed/started the Manhattan Project?
-Assuming the Soviet Union emerged the victor on the Eastern Front and on the Manchurian front, much as it did in actuality, but with significantly more casualties on the former and a greater length of the war by not more than a year, would the Soviet Union be the sole superpower in the world? If so, how much more powerful would the Soviet Union be than the British Empire and the United States?
-Comparing the U.S. and the U.S.S.R. directly in such a situation, could America, having stayed out of the war as I assumed it occurred, have become a superpower purely on its potential military strength as estimated by its economy, or would the gap between the U.S.S.R. and the USA, as a consequence of the latter’s non-participation, have become large enough militarily so that the U.S.A couldn’t be considered an equal in military sense?

Would this military gap, if it would have existed by 1946-7, would have been a permanent one in which the U.S. lack of participation in the War would have made it nearly impossible for the U.S. military to gain parity with the Soviets, or would the economy eventually render the U.S. an equal or greater power, regardless of whether the military fought. In other words, could America have become a superpower without fighting?

Ignoring all of the alternate history above, with the only distinction being that the Manhattan project failed and the scientists in the project were stumped before the end of the war, before either the US or the USSR obtained nuclear weapons, was there a significant difference between the military strength in a purely conventional sense between the two nations? More to the point, would you be worried about losing a total conventional war against the Soviet Union in 1945 (assuming you’re American I guess), as Germany did against them, if neither of the two nations would throughout the course of the war obtain the atom bomb or H bomb, or would you feel assured of victory in the end, and only be aghast at the cost of lives necessary to achieve that end? If it came down to an unconditional surrender, would you feel confident that you, and not Stalin, would be the victor?

Personally, I believe that the reason why the United States became a military superpower was because Japan attacked the U.S. in late 1941, but that it would remain the largest economy, with this margin over any other nation growing larger after the war until it became overwhelming, at least until 1960-5.

This wasn’t going to happen. The oil embargo on Japan pretty much forced them to either withdraw from China (which the military clique would not accept) or attack Western possessions which made American involvement inevitable. Plus by this point the Nazis had already attacked at least two US destroyers.

Eventually, although probably more drawn out than OTL-say by 1950 or so.

The USSR would be far more exhausted militarily and economically and the US and the British would still be natural allies and have greater economic strength combined.

The latter is possible, although keep in mind that the US if threatened could easily build a massive military-until 1940 or so the US had the 16th largest army in the world.

The latter. After all the Soviets throughout the Cold War had consistently larger forces.

Such a war would probably bog down in a stalemate-the Soviets might be able to push the Americans and the British out of the Continent but an invasion of Britain much less that of North America would be practically impossible.

WRT the US developing military might despite non-involvement in the war: take a look at real history. The stuff we had at the beginning of the war was not the same stuff we were using at the end. It was the war itself that drove us to develop and improve weapons. If we sat things out, being able to manufacture huge amounts of ca. 1940-ish tanks and planes and whatnot would have been of dubious value.

Our military was not exactly lavishly equipped when we entered the war IRL. If we spent the war as non-participants, when the Brits and the Commies finally settled the Axis’ hash, we’d just have inferior weapons in very scant supply. If the isolationists had had their way, for whatever reason, on what basis would a government accustomed to a small, cheap military have spent big bucks on development and manufacture of advanced weapons?

Because we could be selling them to the other nations, who were fighting a war? And made big bucks in the process. And could have really grown our own economy, with all that money (or some of it) invested in building up our own infrastructure, factories, etc.

While all of them had cities, factories, transport facilities destroyed, and lots of skilled workers killed or busy in their military, we would have been completely undamaged by the war and wealthy from selling to them.

The Soviets might have emerged as a military superpower (though nearly bankrupt), but the USA would have been the only economic superpower.

^ which was the successful US policy right up until Pearl Harbor: made a whole lot of money out of other nations fighting the Nazis.

Really? Maybe you can cite some examples. As I heard it, most of the folks fighting the Nazis didn’t remain standing for long.

The UK and Russia? Cash-and-carry and Lend-lease and all that?

The usual hand-wavey way around this is to imagine that Japan discovered the Daqing oilfield two decades early. There’s actually an alternate history comic book in Japan based on this counterfactual (覇者の戦塵). I guess this is a pretty popular theory in Anglophone alternate history circles too; if you Google “What if Japan discovered the Daqing oilfield” you get a bunch of threads of varying levels of plausibility on that theme as well, but I don’t know of any English novels about it.

Did either of those programs make a dime in profit for the US? Individual companies might have shown a profit, but since the stuff was sold at discount, often deeply below cost, to the receiving nations, my guess is that the difference was made up by the US taxpayer. Anything we lent them that didn’t get destroyed during the war was obsolete when we got it back. We destroyed it, sold it at a loss, or gave it away. Once again, I expect the US taxpayer was left picking up the tab.
Those programs were a way to help the side FDR wanted to help. They don’t support the idea that the US could have sat out the war and enriched itself selling weapons.

Well, the Wikipedia page sums up Lend-Lease repayment thusly:

This could not have happened. Attacking the Dutch East Indies meant attacking the US Navy. The US Asiatic Fleet had dispersed from Manila Bay prior to the outbreak of war; one light cruiser and five destroyers were at Tarakan, Borneo and four destroyers and a destroyer tender were at Balikpapan, Borneo intending to steam to Singapore. There’s an order of battle here for the Asiatic Fleet. The entire reason for attacking the Dutch East Indies was to get the oil located there; oil that had been cut off as a result of the US led oil embargo.

I thought the Asiatic fleet was only withdrawn from Manila Bay after the Japanese attack there began, because of heavy damage to US facilities. I’m not sure that there would have been the same US presence in Indonesia under the OP’s hypthetical. And even if there were, if the US was still neutral in January 1942, would it have fought against the Japanese invasion of Indonesia? Getting a declaration of war when Hawaii was attacked was one thing, but opting to go to war in the first instance to protect Dutch colonial rule would have been politically trickier.

They were dispersed from Manila Bay prior to the Japanese attack when one of the war warnings was issued. If you check the link it is the location of the vessels at the time of the Japanese attack on Dec 8th (local), 1941. International Date Line and all; Dec 8 local was Dec 7 Hawaii and continental US time. The vessels at Balikpapan were to join Force Z, the HMS Prince of Wales and HMS Repulse. The Japanese were not going to be able to attack the Dutch East Indies or British possessions in the area without attacking the US Navy, sinking US ships and killing US sailors which would make a declaration of war a slam dunk.

I dug a bit to find the exact date of leaving Manila Bay and it was actually 2 days prior to the war warning issued on November 27, 1941, at least for the ships at Balikpapan at the outbreak of hostilities. From here:

If the USA had not gone to war when mainland Britain was under threat of invasion (Battle of Britain), and when mainland China was invaded, why would it have gone to war when a Dutch colony was invaded? I definitely agree with you that it would have been politically tricky to the highest degree, especially when FDR had explicitly promised to not send Americans to fight in an overseas war (when that promise being on the condition that AMERICAN troops, territory, or property wasn’t attacked. Even Wilson, who went to war, did so over things that related to American interests more so than a Dutch Colony being attacked).

The US is a government, not a for-profit organization, oddly enough. And presumably those individual companies paid taxes on their profits, and employed workers who also paid income taxes. So all that helps the US economy.

Yes, at 90% discount. But for most of it, that was probably a generous valuation. This was obsolete equipment, mostly left over from WWI. (The US had not been building up the armed forces and buying much new equipment during the between-wars period.) That we were able to sell it at 10% of the original cost was a good deal. It also meant that we bought stuff to replace it, new stuff, purchased from factories thus putting people to work.

It was a good deal for the US economy, besides being the right thing to do.

The situations were vastly different when China was invaded in 1937 and the oil embargo that was threatening to shut down Japan’s economy in 1941 was put in place by the US over the issue of China. The US was already in an undeclared naval war with Germany in the Atlantic when Japan attacked. Finally, attacking the Dutch East Indies meant attacking the US Navy.

All of your statements except the last sentence make perfect sense. Can you please explain how attacking the Dutch East Indies is a sufficient condition of attacking the US Navy? Were there US sailors in Dutch ships so that attacking a Dutch ship would mean the death or injury of Americans? Was there a secret alliance or tacit agreement between the Dutch and the U.S. that would call for a declaration of war against Japan by the United States if the Dutch East Indies were attacked, and if so, can you provide evidence that could be looked up and verified online (doesn’t need to be a cited source…)? Was the US escorting Dutch ships or doing naval exercises with them?

If I recall correctly, both the U.S. and the Dutch placed an oil embargo on Japan in mid-1941. That does not necessarily imply that if Japan seized the oil of the Dutch East Indies, that it would be an act of war against the U.S. Of course, it would be an act of war against the Dutch since there’s no way of taking their oil without invading and conquering the Indies, since Netherlands had also placed an oil embargo on Japan. Isn’t it obvious that just because the US and Netherlands both placed an embargo on Japan for their respective oil resources, doesn’t mean that the United States was guaranteeing the security of the Dutch colonies oil resources?

Just because two nations decide not to trade with you, even for a key military resource, doesn’t mean that by attacking one of these nations (Dutch East Indies), and seizing the oil, and explicitly not attacking the other (the United States), will necessarily lead to war with both nations, unless there was a military alliance between the two that explicitly said that Japan doing that would mean war with not only the Netherlands (which is obvious), but ALSO America. A policy is a policy, and the burden of proof is on you to either say why I am factually wrong in that there WAS a naval presence of US ships directly in Indonesia, that there was a military alliance between the two, etc. or why in the absence of the two above, and other factors, that a war would nevertheless be declared by the US even though it wasn’t attacked. The assumption that economic and trade relations being broken is an intermediate step toward war is hardly true generally, or from some law of international relations, but was the result of Japan’s particular response to the situation; the breaking of diplomatic relations is actually the intermediate step toward wars, although even this can be settled, but probably only by a loss of national honor if that.

Roosevelt was looking for a way to get into the war to support England before Pearl Harbor, and I’m reasonably confident that the U-boat war would have eventually escalated enough to provide a pretext. Once in an alliance with Great Britain, there is a very good chance that the US would have been drawn into a Pacific war by virtue of Japanese attacks on British Asian colonies.