The what if I saw was basically if the Pearl Harbor attack force was detected en-route before all the attacks, so Japan had time to call off the attacks in the Philippines and divert their forces to back up the other attacking forces.
Most famously, Soviet dictator Josef Stalin raised a toast to the Lend-Lease program at the November 1943 Tehran conference with British Prime Minister Winston Churchill and U.S. President Franklin Roosevelt.
“I want to tell you what, from the Russian point of view, the president and the United States have done for victory in this war,” Stalin said. “The most important things in this war are the machines… The United States is a country of machines. Without the machines we received through Lend-Lease, we would have lost the war.”
Nikita Khrushchev offered the same opinion.
“If the United States had not helped us, we would not have won the war,” he wrote in his memoirs. “One-on-one against Hitler’s Germany, we would not have withstood its onslaught and would have lost the war. No one talks about this officially, and Stalin never, I think, left any written traces of his opinion, but I can say that he expressed this view several times in conversations with me.”… However, the real significance of Lend-Lease for the Soviet war effort was that it covered the “sensitive points” of Soviet production – gasoline, explosives, aluminum, nonferrous metals, radio communications, and so on, says historian Boris Sokolov.
“In a hypothetical battle one-on-one between the U.S.S.R and Germany, without the help of Lend-Lease and without the diversion of significant forces of the Luftwaffe and the German Navy and the diversion of more than one-quarter of its land forces in the fight against Britain and the United States, Stalin could hardly have beaten Hitler,” Sokolov wrote in an essay for RFE/RL’s Russian Service.
As for the idea of moving tank factories- on what? Without Lend-lease, not enough rail:
It should be remembered that during World War I, the transportation crisis in Russia in 1916-17 that did a lot to facilitate the February Revolution [which lead to the abdication of the tsar] was caused by a shortage in the production of railway rails, engines, and freight cars because industrial production had been diverted to munitions," Sokolov wrote. “During World War II, only the supplies brought in by Lend-Lease prevented the paralysis of rail transport in the Soviet Union.”
“In order to really assess the significance of Lend-Lease for the Soviet victory, you only have to imagine how the Soviet Union would have had to fight if there had been no Lend-Lease aid,” Sokolov wrote. “Without Lend-Lease, the Red Army would not have had about one-third of its ammunition, half of its aircraft, or half of its tanks. In addition, there would have been constant shortages of transportation and fuel. The railroads would have periodically come to a halt. And Soviet forces would have been much more poorly coordinated with a constant lack of radio equipment. And they would have been perpetually hungry without American canned meat and fats.”
And how do you build tanks without steel?
In 1963, KGB monitoring recorded Soviet Marshal Georgy Zhukov saying: “People say that the allies didn’t help us. But it cannot be denied that the Americans sent us materiel without which we could not have formed our reserves or continued the war. The Americans provided vital explosives and gunpowder. And how much steel! Could we really have set up the production of our tanks without American steel? And now they are saying that we had plenty of everything on our own.”
So, yeah, those are Russians, leaders of the nation or the army, speaking in that period, admitting that Russia could not win without Lend-Lease.
Mind you, that doesn’t mean the Germans “win” either. The war could have stopped at the Urals, with a constant bleeding war continuing for decades. Several "what if" scenarios have this happening.
With Communist Russia and Nazi Germany battling each other to death, Japan likely would have still done what it did. Leading to GB and the USA vs Japan. Would the USA have bothered to send aid to Russia then? Why? Communism and Stalin was as Evil as Hitler and Nazism. Let them finish each other off, the Allies have another war to worry about.
I don’t think it would have made a bit of difference. Too many pieces moving too many places, and they had already committed themselves to starting a war with the US. Detection would not have changed much if anything.
Without particular strain, I can think of reasons why Stalin in 1943 would’ve felt it a good idea to butter up the Allies about how much he appreciated their aid. He was making nice a lot in those days.
What Khrushchev’s motives were after his overthrow by hard-liners are a matter for speculation, even if one argues that his memoirs (cut/pasted/edited from several sources) are entirely authentic.
One might also snigger at the idea that Radio Free Europe/Radio Liberty is an impeccable historical source. But that would be mean. 
Depends on how early. If somehow we knew, and told them we knew back in mid November things might have gone differently. As to timing and how to open hostilities, if not the eventual fact of japan starting a war with the USA.
Then again, a year ago the USA told the world a couple of months in advance that Russia intended to start a war in Ukraine. And we made sure the Russians knew enough of what we knew that there’d be no doubt on their side that we had this all figured out. They started the war anyhow, and pretty much according to their pre-disclosure plans on their pre-disclosure timetable.
The early Spitfires had a limited on-station time.
The early Mark Is had a service ceiling of 31,900ft, and at 30,000ft could reach a speed of 315mph. Its maximum speed was 362mph at 18,500ft. Its maximum cruising speed, though, was 210mph at 20,000ft, and at economical speed its range was 575 miles. Its combat range was 395 miles, allowing for take-off and 15 minutes of fighting.
Eta, I will concede the point as to whether or not the US should have used nuclear weapons.
I will concede the point. I have been very well corrected in this thread by several people.
Okay, thanks for clearing up my misunderstanding.
But you having done so, I now join those who disagree with you. The United States historically supplied aid to the United Kingdom and the Soviet Union when those countries were fighting Germany and the United States was still at peace. So there’s no reason to take it as a given that the United States wouldn’t have done so in some alternate history.
The United States didn’t send aid to the British or the Soviets out of some affection we held for those countries. We did it because we felt it was in America’s interest to prevent a German victory over those countries. That would have been true - arguably even more true - if Britain had signed a treaty with Germany and the Soviet Union was fighting alone.
Well, let me thank you for an interesting conversation, and for your kind words!
From RAF Manston to Dunkirk is 56 miles. They had plenty of range and on-station time.
[I was wrong about Biggin Hill to Dunkirk being 40 miles, not sure how I got that out of google!]
the “15 minutes of fighting” is irrelevant without context about the area in which the combat referred to is taking place, the type of sortie being flown and the number aircraft being used. (a sporadic 15 minutes now and again is different to a rolling blanket of multiple 15 minutes)
All aircraft are limited in some way. The Spitfire only had around 14 seconds of firing time, doesn’t mean that limited firepower is useless.
Also, contrary to popular belief, the Spitfire was not the only aircraft used by the RAF and fighters were not the only means of providing air cover to the ships and troops. Much ground bombing was done and attacking of e-boats.
Nor was the the typical fighter cover provided just loitering over Dunkirk or the ships (where the suggested 15 minutes would be a bigger issue). It was a dash deeper into France on an intercept mission (where the 15 minutes of combat time is the more likely outcome, but still a perfectly useful length of time)
That was an attitude in Britain in the mid-30s, I believe, though hardly the dominant one by 1938/9. But the problem is that it wouldn’t have led to total destruction on both sides. One or the other would sooner or later emerge as the single dominant power across mainland Europe, opposing/preventing which has always been a basic principle of English/British foreign policy.
Whether the “later” would mean the UK not having to worry about the Suez Canal in pursuing a war in the Far East, at least for long enough to do so, is yet another imponderable.
I’d have to track down the exact timing before, but they were going to call off the attacks if they were discovered up to 24 hours (IIRC) before the attack. After that, the raid was going ahead.
However, if they did abort, they would be in that much worse of a situation. The relationship with the US would be completely shot, but they wouldn’t have the surprise jump.
I don’t recall if they were going to proceed against the other targets or not.
The US was very concerned about possible expansion of Nazi Germany to the Americas. Whether those fears were realistic or not is a separate issue, but that could be a reason to support the USSR.
FDR sent aid to GB as FDR was an Anglophile, and GB was a major trade partner and ally. FDR despised Stalin and communism.
There is little to choose between a Nazi win or a Commie win. They both killed off massive numbers of their own peoples. Why would it be in Americas interest to prevent the Nazis and Commies from destroying each other?
True, there were more Hurricanes. But they were somewhat similar.
An interesting historical question is whether lend lease was more effective in prolonging the mutual meat grinder than sitting out would have been.
Probably optimal play from the US POV would have been to give the USSR enough to keep them in the fight from 1940 to maybe late 1943, so as to keep them bleeding badly themselves while also bleeding the Nazis’ real hard.
And then later, post-Normandy, the US should have pulled the rug out from under Stalin, preventing him from steamrolling eastern Europe while the US/UK and freed western Europe rolled up the Nazis all the way to the Soviet frontier. By late 1945 there would be no place for a future Warsaw Pact to exist. all of Europe would be on the free side, and if an Iron Curtain was to descend, only Soviets would be on the east side of it.
Interesting idea.
At some point in the Yalta “allies” story, Stalin secretly decided the alliance ended when the Nazis were defeated. Thereafter he was playing a double-game aiming for post-war supremacy over his so-called allies: the US/UK.
Had the US/UK come to an equally cynical / clear-eyed conclusion at or before Stalin did and had they played WW-II to that end, everything from 1945 to now might be very different.
I had a visiting history prof in college who advanced a similar POV. He said that we should have threatened Stalin with nukes, and maybe even used one or two, until he (Stalin) backed down.
I believe the US had a plan to defeat the Soviet Union, using 34 atomic bombs dropped on 24 Soviet cities. They problem was they didn’t have that many atomic bombs at the time. They had components for bombs, which would have to be assembled first.