Jason, a reversal for the USN at Midway would have meant no Allied offensive before mid-1943. Japan would therefore been free to threaten the Allied communications to Australia by resuming to their offensives directed at Port Moresby [although it would have been a hellish outpost vs the air power and submarines building up in Australia], and the Guadalcanal-Tulagi steppingstone could have ended up with the JA occupying New Caledonia. But the sea lanes to ANZUS allies still could have been sustained, and the JA only had notions of sending a single regiment to secure Fiji and that probably would have failed. Outposts such as Midway and Dutch Harbor [what-if in larger scale] would have remained problematic for JA and IJN.
The only roads to victory for Japan after defeating the USN at Midway would have been even more grandiose operations than occupying the Pacific island defense belt and the East Indies: India or Australia [choose one; Hawaii effectively was a third but probably too far and not even decisive, and the JA was not interested]. The Japanese Army could not wage a campaign in Australia without shutting down the China War, the very impossibility that led them to war vs the US. India proved a much tougher nut to crack after initial successes. A purely naval campaign in the IO could only have worked in combination with German-Italian successes in the Eastern Mediterranean, but Germany bogged down in Russia and lost initiative in North Africa, The European Axis in any event could do little to assist Japan apart from a diplomatic line drawn East of Aden to deconflict their wishful conquests, leaving Middle East oil in German spheres. Speaking of which, the long term value of the Axis was already dwindling with the German refusal to provide badly needed machine tools to Japan, while the latter refused any German economic exploitation of occupied China.
Ken, even though I tend to post a lot about Japan and such, it by no means equals me knowing everything. After all the great majority of Americans can't claim to know all American military matters either. And as I said before, the history speculation debate doesn't grab my interest too terribly much. Nor does my attempt to continue with rebuttals mean that I have a preference for Japan to have won. Well TBH the feelings creep in once in a while lately. Partly depending on current affairs, kind of makes it a bit regrettable, at least from Japan's POV with today's China and DPRK. But also because my major was International Studies:Asian studies and the university degree has done nothing in providing light about history issues that still linger thus that too adds to sentiment for Japan. Well that is a topic that can make for a very big post on its own. Main point being that I don't mean to make the rebuttals from of an emotional feeling of strongly wishing that Japan had won. But in the other way, I don't feel so positive about the US winning in the Pacific either. Well anyway, that aside, some more rebuttals, because I tend to over think things, but does not necessarily mean the following rebuttals are good. If not, then at least maybe they could serve as good entertainment at the least and warrant sparing me from a sharp tongue
Well first off, not a rebuttal. I agree about JA limited progress towards India. They seemed to have been stuck there in Burma. In addition to total stretched Japanese army forces, Burma was a terrible place because of the monsoons, jungles, and disease prone ridden environment.
However, AFAIK (hence my still limits in total knowledge on Japanese military), a main objective of the Burma campaign, was to cut off ally aid flying over to China. However Operation Ichi-Go seems to indicate that even in mid 1944, the nationalists Chinese were still rather weak. Additionally, when mid 1945 came about, the Soviet Union was of course ready with lots of strength and came crashing through Manchuria, but no such action had happened from the Chinese. That would seem to indicate that ally aid flying over the hump has not been able to build up the nationalists into being a serious threat again. Thus the JA wouldn't really have needed to achieve the victory that the Battle of Imphal attempted in the Burma Campaign in order to achieve a final victory in the Pacific War.
For Australia, I think the Japanese never had a plan to capture Australia. Certainly wouldn't have been possible should it have become a necessary requirement. But maybe it wouldn't have been necessary either.
For Midway, I agree that Japan wouldn't be able to capture and keep it in secured control. But even in that case, a big naval battle would take the place of the Battle of the Philippine Sea. Maybe not necessarily at the Philippine Sea, but a big one nonetheless. But this time instead of circumstances that resulted in the Turkey shoot. it would be a more or less even match up again like at Midway, rather than the real 1944 Battle of the Philippine Sea. Again, taken the variables of the supposed 1942 speculation of a different Midway and Guadalcanal, then it means Japan still having a fair number of experienced pilots, the US having lost many experienced pilots (3 US carriers lost at Midway control -- I know the speculation is killing.. but to finish it), and equal number of carriers, 7v7 or something. Of course the US side would still have radar, well trained pilots to fill in for the lost experienced pilots from a robust training system, and new Hellcats vs likely still the getting old zeros. So I don't say that this new speculated 1944 showdown has the US at a disadvantage, but the match is certainly closer to equal than the match up between the two in the actual Battle of the Philippine Sea.
I would finish with one more rebuttal towards a point raised by Josh and Brian, which is the degree of will to fight in the US. I think there are suggestions of a limited will, even though there was the uproar to fight following PH. IIRC news of many Americans dying on islands was still not taken well back in the US. US commanders gave very optimistic time scale for a number of the islands to be captured such as Peleliu or Iwo Jima. I wonder if it was just that, foolish optimism, or by saying so so as to motivate the men that have to actual get on the beach and fight by making them feel less fear to go and get it done. Ultimately, the Japanese objective was to never take American land itself. Would the Americans really still be highly motivated to go and fight on the opposite side of the Pacific with an enemy that really had no intention whatsoever to get Hawaii or go as far as California, Chicago (1:31) and so on, if Midway was a major defeat? The SU was fighting for survival. So was the UK, and France, but the US was not in that kind of fight. US will to fight was certainly underestimated after PH and in the 1942 campaign in the Philippines, and Guadalcanal. But even with that, there still seem to be indications of a limit.