The US would be involved in a corps-level offensive
still think you are seriously underestimating the politics of this. Particularly the desire in the US to hit the Japanese hard and soon. As to the SLOCs, Fiji and Samoa are on that route too. While New Caledonia has valuable minerals (that were exploited during the war and after). The Australians raised a hell of a stink after the British threw away the 8th Division at Singapore. Enough so that Churchill was pretty much forced to send the AIF home, with the remaining division going home after North Africa was won. Australia has more clout than Churchill liked and for that matter King had a lot of clout with FDR.
The US would be involved in a corps-level offensive against the Japanese in Papua, which combined with the air war and various alarums and excursions against the Mandates, would be enough war in the Pacific, one would think...
By the summer of 1942, New Caledonia, Fiji, and Samoa were all better defended than Midway was, and we all know what happened when the IJN tried for Midway...
As far as Australia goes, Curtin was well aware Australia was the junior partner in the Pacific, and after Coral Sea, the Australians knew the Japanese were out of luck in the Southwest Pacific.
Basically, the decision comes down to liberating France (and bringing 8-16 divisions into the Allied order of battle) in
1943, and - potentially -
defeating the Germans in 1944, or forcing the surrender of Italy (or at least half of it) and bringing about 3-4 divisions into the Allied order of battle in 1943, but delaying VE Day until 1945.
Seems like a risk worth taking, especially because the troops, air forces, naval forces, merchant shipping, and yes, the LSTs were available in 1943 for ROUNDUP or some variant.
As far as air power goes, here are some numbers from Cajus Bekker's
The Luftwaffe War Diaries:
In August,
1943, the German home defense forces (daylight fighters) reached their all time high in frontline aircraft: 405 single-engine (Me. 109 and Fw. 190) and 80 Me. 110/Me. 410; two full wings (JG 3 from the eastern front and JG 26 from the Channel) were brought "home" to Germany, as were separate groups from JGs 27 and 51 in the Mediterranean theater and JG 54 from the eastern front.
Interesting thing about the above is the need for daylight fighters in the hundreds as early as the spring of '43; given the above, it appears that 300-400 modern fighters is about what the Germans could consider a "reserve" in this period, and so even if those numbers are doubled or even tripled, it is still far less than what the RAF and USAAF could deploy over the UK, Channel, and northwestern France.
What we've kicked around in the previous thread was ROUNDUP in NW France as an OVERLORD analogue in July of 43 (same time as HUSKY, and the equivalent of the HUSKY assault force OOB as the assault force for ROUNDUP), following Sardinia-Corsica (BRIMSTONE-FIREBRAND) in the spring of
1943, with southern France (ANVIL) in the autumn. ANVIL opens up the French Mediterranean ports (in any scenario).
The above requires a firm commitment from all parties at 2nd Washington (summer, 1942) with a strategic defensive in the Pacific and an enlarged "SUPER" TORCH in November, 1942, using additional resources not sent to the Pacific. The enlarged TORCH shuts down the Axis in North Africa in the winter of 1942-43, this providing enough time for the assaults listed above in
1943.
Considering the "spread" of potential targets for Allied amphibious assaults in 1942-43 the Germans have to guard against, and the reality they have to try and do something in Russia, and the odds seems well within reason.
Others may differ, but the potential payoff of VE Day in the summer or autumn of 1944 seems like a risk worth running ...
Considering the historical record of where and when the Allies were campaigning in 1943, it seems pretty clear that given an early enough decision, there was an opportunity to concentrate in NW Europe and actually achieve something in 1943, rather than marking time in the Med, SEA, SW Pacific, South Pacific, etc.
Best,