If the US stays out, then in early 1942, the UK benefits by better LL deliveries because there is no Operation Drumbeat sinking US ships along the Atlantic Coast.
Yes, that is a benefit as long as that continues.
There may be some political resistance in the US to providing LL to the USSR because they are not in the war against Japan. If so, Germany does better on the Eastern Front.
*If* that political resistance/reluctance is successful and carries the day. It might still be parried by the daisy-chain logic that Soviet survival and Soviet victory is *still* nevertheless good for the USA and for assuring American (and Anglo-American) earliest and most decisive victory against Japan. The logical daisy-chain is thus: The longer the USSR survives and better it performs against Nazi Germany, the better Britain and the British Empire and British industry will do, and the more strongly the British Empire will be able to assist America and China in halting and crushing Japan. A collapsed Soviet Union means loss of a major source of strategic minerals for the USA and Britain, capture of resources for Nazi Germany, and a Britain and British Empire thrown back on to the defensive, hardly able to take any initiative against Japan, leaving the weight of the Japan more completely to America and China.
And if the Administration has to hypothetically accept, for wartime unity of the anti-Japanese war effort, a policy of only offering Lend-Lease supply to Allies fighting Japan, like Britain, its Empire and China, but not those who are not, like Soviet Russia, there are still potential work arounds. Some degree of assistance couched as "strategic trade" for certain rare minerals from the Soviet Union in return for particularly vital American supplies, and called trade instead of Lend-Lease or any sort of giveaway. And, items outright intended ultimately as aid could be in a sense "laundered" as aid to Britain, and Britain can then aid the USSR itself, as it did in OTL.
Lack of US bombing, build up of US troops in Britain posing an increased invasion threat from 1942 on, and especially lack of US participation in ground campaigns in the Mediterranean in 1942 and 1943, now those all would be detrimental factors for the USSR. But given that it took quite a while for western Lend-Lease to build up a "head of steam" and make major gap-filling contributions, lack of direct American belligerency is not likely to directly effect outcomes of the Nazi summer Case Blue Offensive, or even the Battle of Stalingrad, only starting to affect Soviet fortunes negatively in the post-Stalingrad victory timeframe. And by then, America will probably be at war with Germany, probably ready to participate in the air and on the ground, more nimbly, quickly and strongly, without the same need for as lengthy a ramp up as it required after December 11, 1941.
Torch does not go forward the same way and it is unclear if the UK can pull it off by itself because there may be more determined Vichy resistance.
I agree
Starting in late 42, early 43, the bombing of Germany is somewhat reduced. We can send planes to the UK but their ability to replace flight crew if they do daylight bombing the way we did may not be as strong without us.
I just don't think the British will be trying much daylight or precision bombing at all without the Americans doing the missions.
Taking all of this into account, it may take a lot longer for the UK to get to Italy on the Southern Front and the Axis may do quite a bit better on the Eastern Front.
For as long as the US is not engaging ground combat units in Europe, I am not really certain there is a time when a) Italy is ready to make the leap to outright capitulation, and b) The British Empire is ready to brave an invasion of mainland Italy, or any spot on the European mainland, as opposed to the continent's offshore islands like Sicily, Sardinia, Corsica or Crete. As for the eastern front, as I was getting at, the Axis would be doing comparatively better for awhile by the Soviets not getting as much momentum or strong follow up results from the Stalingrad victory.
The US probably picks up some momentum in the Pacific in 43 and may take the Marianas in early 44 or late 43 moving everything else forward by 6 months or so.
Marianas in late 1943 just doesn't seem possible with the Navy builds just rolling off the slips by then. Everybody talks about the Central Pacific drive being more important, relevant, necessary than Mac's theater in the Southwest Pacific, because it did ultimately get US forces quite close to Japan and smashed their fleet to bits, and because Mac is such a douche its fun to ridicule him. However, due to when our major two ocean Navy modern carrier and battlewagon builds were set to come down the slips and be ready to fight alongside their fully equipped fleet train, late 1943 and early 1944, and no earlier, the Central Pacific drive could hardly have been accelerated. But, shoving more men and AirPower and the limited fleet we did have, under the cover of land based air power in the Solomons, New Guinea and Bismarcks, could have actually made things move faster in Southwest Pacific and that region throughout 1943, to get Army and Army Air Corps forces in a nice advances position in Southwest Pacific/New Guinea to start doing the hop to the Philippines with the arrival of superior fleet in early 1944. More Army and Army Air Corps resources, though it would have been logistically long and thus inefficient, could have turned 1943 in Burma from a no-progress year into a progress year, possibly opening up the Ledo Road/Stilwell Road as well.
Operation Matterhorn, the China-based strategic bombing campaign to really strike the Japanese home islands on a sustained basis, did not really get started until early 1944, I think, although the idea was there through all 1943. Some major raids were launched from China, but it turned out to be a stimulant for Japan's Ichigo offensive, which overran all the forward most American air bases in east and southeast China, causing the capture or preemptive destruction of tons of infrastructure and supplies and reducing the effectiveness of strategic raids for months. Until, after the July 1944 capture of the Marianas, and repair of airfields, the main strategic bombing raids were staged from there instead, bases that the Japanese could not assail.
A possible positive consequence of taking the Marianas in early 1944 instead of mid-1944 might be that they are the main base for strategic bombing of the Japanese home islands from the beginning, instead of China, leaving Japan less motivated to launch Ichigo, which devastated the ChiNats, and not really believing Ichigo would solve their problems or defend their homeland much. Now the US bombing from China campaign probably wasn't the *only* motive for Ichigo, increased shipping losses for Japan probably meant they felt a contiguous north to south land route from northeast to Southeast Asia was desirable, and they might hav sensed some decay in Nationalist China they could exploit. But maybe it is something they end up not trying, or not trying until too late and the US can bring aid effectively to bear across the Burma Road or Pacific.
On the other hand, it is more likely that the US enters the war in Europe - perhaps after taking the Marianas and locking in a victory over Japan.
Then or before or whenever or sure.
But that could involve a 2 year delay and in that time the Axis might batter the USSR badly enough to establish a static front along the Volga or even as far as the Urals.
A Volga-Urals line would be a super generous estimate for an Axis frontline in 1944 and super unlikely to be met just by absence of US forces, even if you combined it with slashed LL, that I don't think would be slashed as drastically as estimated. The Dnieper and Lake Ladoga and Gulf of Finland is really the most forward plausible stall line I can imagine the Germans holding until 1944 under the worst of circumstances for the Soviets with a non supportive US, but a fully supportive British Empire. And the Soviets could also still manage by mid or late 1944 without a continental invasion having taken place yet to reach a line of Memel-Lemberg/Lvov-Odessa, which would be less extended for both sides.
A German advance to the Urals, or just to the Volga, implies Soviet losses in Stalingrad and the Caucasus making Nazi forces a new threat axis to the British position in the Middle East, now from the north. The British would then consequently find themselves heavily engaging that southern Nazi prong via the Persian Gulf, Iraq and Iran in collaboration with surviving Soviet forces in the Transcaucasian republics to keep the Nazis out. That would be priority placement over finishing off Libya, and for British Indian troops over any Burma campaigning.
LL was very important to the USSR and the reduced bombing of Germany would mean that armament production would go up and somewhat less resources would be used for AA.
All true. And, despite any defeats the Axis may suffer in North Africa and Sicily, folks in Italy like the Italian King may sense this relatively more secure German power, and hesitate to overthrow Mussolini in 1943, or try to move for capitulation, which also eases Germany's troop situation. So a USA just declaring war in 1944 would have a lot of "defeating Germany" work ahead of it, against a well fortified foe, with heavily spent allies. By late summer 1945, it should be getting atomic weapons, or possibly delayed into the fall if the program had been treated as less urgent, but it won't be an instant win button without lots of luck to just drop one or two. Massing multiple bombs for synchronized delivery and appropriate tactics for assured, survivable delivery and detonation and effect, will be very important.
The US was doing quite a bit more than playing Chicken with submarines in the Atlantic.
Had established a US Naval base on Iceland in July 1941. Including US Marines and Navy aircraft
Was actively assisting the British in tracking down blockade runners, the armed merchant raiders, and efforts by Germany to use neutral shipping to bring war essential material to neutral Spain, Vichy France, Turky.
Had US Navy and Army instructors in Britain. This included USN pilots flying in Coastal Command aircraft on ASW patrols as instructors.
Selling the USSR war material on credit, and assisting in trans Pacific shipping to help expedite the movement.
These were all actions hostile to Germany, and helpful to the Allies. The bolded seems the most serious and belligerent to me.
But you know what these were not? They were not air campaigns/bombing campaigns over Axis territory, let alone ones involving risk of capture of US personnel.
They were not deployments of ground combat units where they were in likelihood of contact with hostile ground forces, nor invasions of Axis occupied territories, not indeed any territories, under Axis direct or indirect influence, where local armed forces were likely to violently resist the arrival of US forces.
Was discussing with Petains government actions that might bring France back into the war. Occupation of specific French colonial territories was the big one. Petains attitude of the Allies invaded German occupied France was the other big question.
Without a US DoW on Germany, American peaceful occupations of various French owned islands in the western hemisphere, or in the eastern or southern Pacific like Tahiti or New Caledonia would have been conceivable. Possibly, at a stretch, Madagascar in the Indian Ocean. American peaceful occupation of unoccupied Vichy France or French North Africa was not something anyone believed could happen, and not anything the Roosevelt Administration imagined it could do forcefully or otherwise, without Congress having declared a state of war between Germany and the USA.