Pacific war with Europe at peace [closed]

Question

January 1939, Hitler has a dream where he sees that he will lose the war he is planning. Thus, he renounces to war and doesn't invade Poland. Mussolini does the same dream a few weeks later and similarly decides to avoid any open conflict.

Given the situation of Japan at that time, strengths and weakness of Japan/American armies, mindset of Japan leaders, ... I would like to know :

• How would this have changed the Pacific war ?
• Would Japan have attacked USA anyway with the risk to see the British empire putting all its forces in this war ?
• Would Russia, France, Germany and Italy have been involved in this conflict ?

Answer 1

This is at best informed speculation.

I'm going to assume that Japan continued the war in China, which started before 1939. This was largely independent of European events. The Japanese would have been unlikely to invade Indochina with France remaining strong, but aside from that I'd expect something like the Pearl Harbor attack. The Japanese went into that attack knowing that they had very little chance of winning in any case, considering it a matter of national honor.

The US had some fairly strong forces in the Atlantic as of Pearl Harbor, and some US warships were involved in facing the Axis (including the carrier Wasp). They would have been available in the Pacific, and that makes it quite possible that the Japanese would have sunk a carrier at Pearl Harbor.

It seems unlikely that the Soviet Union would have gotten involved, as they had European interests to protect. They would likely have gotten more expansionistic. France would likely have stayed out if Indochina got left alone. The British are more of a question. Historically, Japan attacked the British as well as the US, so I'm going to assume the British were in the war. Germany had no interests in the Pacific. Given Hitler's dream, and Mussolini's lack of power, I'd expect Europe to remain at peace for some time.

The lack of a strong Navy to face in Europe would have allowed the British to send more naval forces to the Far East, and the British-controlled territories would be shielded from direct attack by the neutral French Indochina. This might have made the Japanese army more interested in fighting in the Pacific.

So, I'd imagine a somewhat different course for the Pacific War. One interesting thing is that the US sent most of its available resources against Japan in 1942, so not having the war in Europe would not have affected the initial course of the war all that much. The US juggernaut could not take place until the US had built enough aircraft carriers, so the Central Pacific offensive would have started pretty much on historical schedule.

One big difference would be the provision of landing ships and craft. Historically, the production of destroyer escorts needed for the Battle of the Atlantic cut heavily into landing ship production, and most of them were facing Germany until around the end of 1944 in any case.

Answer 2

I do not believe Pearl Harbor would have happened anyways. Japan's motives for attacking Pearl Harbor were mostly about securing oil imports. The US had embargoed Japan in an attempt to stop their aggression in China. Attacking Pearl Harbor was an attempt to make the US back down. Without a war raging in Europe, it's possible that Japan could just have found a different source for oil; maybe Romania?

Answer 3

Without a European War that took out France and the Netherlands and had the attention of the UK, and had the USSR fighting for its life, Japan doesn't take the risk.

Note that despite the war between the USSR and Germany, Japan never poked the Russian bear, even when it was apparently on the ropes in 1941/1942, the result of thoroughly getting its ass handed to it in 1939 at Khalkhin Gol courtesy of Zhukov and the Red Army. That cautiousness would likely have extended to European powers not distracted by events at home.

Consider the strategic situation: Japan attacked Pearl Harbor because they needed to cripple the American fleet, because they had to attack the Philippines. They had to attack the Philippines because they needed to secure their flank in order to grab Indonesia and Indochina for their resources. But that meant they had to attack Hong Kong and Singapore to also secure their flanks. So they're already at war with Americans and the British. Attacking Indochina means bringing in the French. Attacking Indonesia means now the Dutch are in the mix as well, as they were in reality (although they were curb-stomped).

Just on the naval front, in 1939 the Royal Navy was still the largest in the world, with 15 battleships (+9 under construction), 7 carriers (+6 under construction), 65 cruisers of all sizes (+26 under construction), 113 modern destroyers (+24), 53 modern subs (+11).

The French had 7 battleships (+4), 1 aircraft carrier (+1), 19 cruisers (+3), 78 destroyers (+27), and 81 subs (+38).

By late 1941, the US had 17 battleships (+15), 7 carriers (+11), 43 cruisers (+40), 171 destroyers (+188), and 114 subs (+79).

The Japanese Navy, in December 1941, had 10 battleships (+3), 12 carriers (+7), 38 cruisers (+6), 126 destroyers (+43), and 68 fleet subs.

So, what does that mean? On the naval front, and using only the 1939 French and British numbers, in December 1941 the Japanese are outnumbered:

• 39 to 10 in battleships;
• 22 to 12 in carriers (given the superiority of Japanese naval aviation, this is actually pretty close, if not in Japan's favour);
• 127 to 38 in cruisers;
• 362 to 126 in destroyers; and
• 248 to 66 in submarines.

Now the Japanese had advantages: naval aviation, as mentioned, and the Long Lance, but quantity has a quality of its own. The Japanese could count, and they knew that in a prolonged struggle they'd be stomped by American and British shipbuilding, so the numbers would always get worse.

And then that doesn't get to the sizes of the merchant marines that could carry supplies and troops to the front, nor the air forces and armies.

The question was whether the suicidally overconfident military government in 1941 looks around and realizes they don't have an opening. In 1941, they could fool themselves into thinking the French were out of it, the British were on the ropes, the Dutch weren't worth worrying about, and the Americans didn't really have skin in the game aside from a quasi-colonial status with the Philippines, so they might be convinced to back down. With the British not distracted, the French with colonies they would fight hard to keep, and the Americans still the same threat, things are different. I suspect they would have swallowed their pride and tried to negotiate a way out.

Answer 4

It's hard to speculate at this, but I think Italy under Mussolini would have carried out Hitler's role, effecting very similar results. Since Germany swore off war, Mussolini would have no trouble taking them over.

One could make the argument that Mussolini was more tactically conservative than Hitler, so blitzkrieg wouldn't have been as much of a thing. This might have meant years of trench warfare instead of a quick takeover of Europe. Heck, in that scenario, Europe might still be at each other's throats in one form or another to this day.

Answer 5

With European powers unoccupied, attacking Perl Harbor would have been a complete and utter suicide for Japan (not like it was much different in our real timeline, but Japan's own leadership would clearly see it).

If Japan would have done it anyways, Britain would certainly join forces with US, and Imperial Japanese Navy would have been severely pressed much earlier in the war. If Britain would send out expeditionary forces as well, Japan may have been defeated within a year.

This, however, would have created an opportunity for Hitler to make his strike, and successful invasion of Britain would be very real. In essence, Japan may have sacrificed itself to allow another Axis power to win.

Answer 6

No Nuclear Weapons, at least not yet

Assuming that Pearl Harbor and much of the rest of the Pacific war went on as others have suggested, one big change would have been at the end. On the one hand, with the US fighting only one big war instead of two, they would have likely finished the war sooner. But on the other hand, the initial motivation for the Manhattan Project was the war against Germany and fear that Germany was working on nuclear weapons - e.g., Einstein's letter.

While the US did end up using the bomb on Japan, that was not the original plan. Without the war in Europe, and with an accelerated timeline for the Pacific war, the Manhattan Project might never have even started, and almost certainly would not have produced usable weapons before the end of the war. That means the end of the war, while sooner, might have involved more American casualties in the final battles. Long-term effects might be even bigger - without a Manhattan Project and Soviet spies, we might have never gotten to MAD and the Cold War could have been quite different.