[Lancer44]

Originally Posted by PanzerGeneral

Our massive direct military support of the USSR and our great appeasement at Yalta was entirely unnecessary as the USSR would have gone on fighting and beating the Germans without our assistance. Had we not aided them, the Red Army would have advanced at a somewhat slower rate allowing the US and British armies to occupy Germany, central Europe and potentially much of eastern Europe in advance of the Soviets thus ensuring that the Iron Curtain was moved much farther to the east of where it actually stood for half a century. Had we not supported and appeased Stalin to this unbelievable extent, the Cold War might have been entirely avoided.

I totally agree with PanzerGeneral but want to add a little correction:

Soviets and now Russia always denied that lend Lease supplies were vital for their industry. I think that the most important of all comodities delivered to USSR were 229,000 metric tons of aluminium. How important it was you can see reading letter of Stalin to Roosevelt:

FROM PREMIER STALIN TO THE PRESIDENT, Mr. ROOSEVELT
In taking this opportunity to send you a personal message through the courtesy of Mr. Standley, who is leaving for Washington, I should like to say a few words about U.S. military deliveries to the U.S.S.R.
The difficulties of delivery are reported to be due primarily to shortage of shipping. To remedy the shipping situation the Soviet Government would be prepared to agree to a certain curtailment of U.S. arms deliveries to the Soviet Union. We should be prepared temporarily fully to renounce deliveries of tanks, guns, ammunition, pistols, etc. At the same time, however, we are badly in need of increased deliveries of modern fighter aircraft-such as Aircobras-and certain other supplies. It should be borne in mind that the Kittyhawk is no match for the modern German fighter.
It would be very good if the U.S.A. could ensure the monthly delivery of at least the following items: 500 fighters, 8,000 to 10,000 trucks, 5,000 tons of aluminium, and 4,000 to 5,000 tons of explosives. Besides, we need, within 12 months, two million tons of grain (wheat) and as much as we can have of fats, concentrated foods and canned meat. We could bring in a considerable part of the food supplies in Soviet ships via Vladivostok if the U.S.A. consented to turn over to the U.S.S.R. 20 to 30 ships at the least to replenish our fleet. I have talked this over with Mr. Willkie, feeling certain that he will convey it to you.
As regards the situation at the front, you are undoubtedly aware that in recent months our position in the South, particularly in the Stalingrad area, has deteriorated due to shortage of aircraft, mostly fighters. The Germans have bigger stocks of aircraft than we anticipated. In the South they have at least a twofold superiority in the air, which makes it impossible for us to protect our troops. War experience has shown that the bravest troops are helpless unless protected against air attack.
October 7, 1942
Sources:
http://www.shsu.edu/~his_ncp/LendL.html
Interesting figures here.
http://www.theeasternfront.co.uk/lendlease.htm
Here a bit about soviet alumnium industry:

On the basis of the Tikhvin deposit's potential, 1929's Decree of Government Structures by the Soviet of Labor and Defense approved the construction of two aluminum complexes—one in Volkhov and one in Dnepr. Combined, these sites, with their alumina production lines and hydroelectric power, would have an annual aluminum production capacity of 20,000 tonnes. As a result, full development of the Tikhvin bauxite mine began in 1929; in 1930, construction of the Volkhov and Dnepr aluminum smelters began. The construction proved challenging owing to a general lack of engineering and design experience with aluminum smelters and the need to incorporate the new alumina production technology. Thus, the French company Ale Forge Comarg was commissioned to assist with developing the production facilities. On September 14, 1932, the first alumina was produced at Volkhov using Tikhvin bauxite. In April 1934, alumina production from Tikhvin bauxite began at Dnepr.
Complementary to these activities, various departments and laboratories that were focused on nonferrous metals in general and aluminum in particular were reorganized in 1931 into a light metals research institute (NIISaluminiy) and a design institute (Hyproaluminiy). Later, these organizations were combined as the All-Union Aluminium & Magnesium Institute (VAMI), which is today known as VAMI Ltd. The task of the new institutes was to coordinate research and development as well as the overall development of the Soviet aluminum and alumina enterprises.
During the construction of the Volkhov and Dnepr smelters, it was decided to increase the country's total aluminum production capacity to 70,000 t/y. The decision was based, in part, on the 1931-1932 discoveries of additional bauxite deposits in the Ural Mountains. Hence, two new alumina production facilities were planned—a 40,000 t/y plant near the Tikhvin mines and a 60,000 t/y plant in the Urals. The Tikhvin plant used a wet-mix variation of the alumina production technology employed at the Volkhov complex.
In 1933, development of the bauxite mines near Nadejdinsk (currently known as the Northern Ural bauxite mines) was initiated, as was construction of the Ural aluminum complex. This complex was built near Kamensk-Ural because of the nearby bauxite and coal reserves. The project stipulated construction of an accompanying 70,000 t/y alumina facility that would employ the Bayer method to treat the local hydrorhillite bauxite. However, after reassessing the quality of the diaspore Northern Ural bauxite deposits, it was decided to instead employ a novel autoclave method of bauxite digestion. In some stages of the construction, design concepts from Pechiney were employed. In 1939, the first alumina was produced at the Ural complex.
In 1941, there were four alumina plants in the Soviet Union. With the German invasion of Russia, however, this situation changed drastically:
Operations in the European part of the country were shut down. Equipment from the Dnepr and Volkhov complexes as well as the Tikhvin alumina plant were dismantled and sent to the Urals.
The construction of a new alumina plant in Northern Ural as part of the aluminum smelter in Bogoslovsk (today known as Krasnoturjinsk) was changed considerably—incorporation of a Bayer processing plant was abandoned in favor of the sintering method because of the availability of the dismantled equipment from the Tikhvin plant.
On June 17, 1943, aluminum hydroxide was produced at Bogoslovsk; on April 17, 1944, the calcination furnace was put into operation and the first alumina was produced. Only after the war was the Bayer flowsheet adopted at the plant (utilizing equipment from the sintering shop).
Source: http://www.tms.org/pubs/journals/JOM/9608/Smirnov-9608.html
You can clearly see that without Lend Lease aluminium deliveries soviets would never produce enough aeroplanes to gain air superiority over Luftwaffe.
And here look at aluminium production after the war in 1953: http://www.ndu.edu/library/ic2/L54-032.pdf
Roosevelt could put a lot of pressure on Stalin regarding Eastern Europe after war using Lend Lease as leverage. He did not wanted to do it.
Just because of that Roosevelt can be called an "architect of Cold War".

Cheers,

Lancer44