In World War II, the Eastern Front battlefield of the Soviet Union was the largest battlefield in the world, the Soviet Union alone faced the attack of more than 4 million elite German troops, suffered huge losses, the main army of the Soviet Union suffered a devastating blow in the early stage, only the Battle of Kiev was surrounded by more than 600,000 people at one time, and the entire Southwest Front was almost completely annihilated. But the Soviet Union was not isolated, and in fact the Soviet Union still had many allies. For example, Stalin once said that the Soviet Union's greatest ally was the United States.

Stalin once said: More than 60% of the soviet union's factories were technically assisted by the United States, and the United States was the most important ally of the Soviet Union to win the war, but as we all know, the Cold War period between the United States and the Soviet Union can be described as incompatible, why can it be so close during World War II?
As early as early 1937, in the face of the threat of fascist aggression, Roosevelt had quietly set about improving relations with the Soviet Union, hoping that it would work with the bourgeois state against Germany and Japan, and in January sent Joseph Davis to Moscow to win Stalin's trust. In June, he abolished the Department of Eastern European Affairs, which was actively anti-Soviet at the State Department.
However, due to the signing of the non-aggression pact between the Soviet Union and Germany in August 1939, and the subsequent manifestations of chauvinism by some of the Soviet powers (the partition of Poland, the so-called chauvinism is hegemonism), Russia's relations with the United States fell to a low point in the following year and a half.
On June 22, 1941, the Soviet-German War broke out. On 23 June, the U.S. government issued a statement stating that "any defense against Hitlerism, any concentration of forces, wherever such forces come from, will hasten the inescapable defeat of Germany's present leaders and thus benefit our own national defense and security." Today, the main danger to all parts of the Americas is Hitler's army. ”
On June 24, President Roosevelt said the United States would do everything possible to aid the Soviet Union, lifting the freeze on Soviet assets worth $39 million. On the 25th, he announced that he would not implement the legislation in the Soviet Union so that American ships could sail to Soviet ports. On the 30th, Wells considered $1.8 billion in material assistance from the Soviet Union. On July 8, Roosevelt and the British joined the Vatican in explaining the Anglo-American position on aid to the Soviet Union and demanding that potential Catholic opposition be stopped. On the 10th, he told the Soviet ambassador that he wanted to deliver the supplies requested by the Soviet Union on June 30 to Russia by October 1.
It can be said that Roosevelt did everything in his power to aid the Soviet Union. After the United States officially entered the war, the representatives of Britain, Russia and the United States held talks, and most of the list of needs and materials proposed by the Soviet representatives at the meeting was met.
This includes more than 70 major projects and more than 80 projects of medical supplies. According to the Trilateral Agreement of October 1, britain, the United States and the Soviet Union, by June 30, 1942, Britain and the United States would supply 1.5 million tons of Soviet materials, worth about $1 billion
Among them, including 400 aircraft and 500 tanks per month, plus 1,256 anti-tank guns and 5,000 jeeps, etc.
In order to alleviate the depletion of Soviet funds, Roosevelt also told Stalin that the total value of $1 billion worth of Loan-Lease French aid would be immediately available. And the restitution begins in the fifth year of the war and is repaid in 10 years. ???
The United States actively assisted the Soviet Union, especially after the implementation of the Lend-Lease Act, which gave great help to the Soviet Union in resisting fascist aggression. As Stalin pointed out: "If it were not for the use of these machines (airplanes, cars, etc.) through the Lend-Lease Law, we would have been defeated." It can be said that without the support of the United States, it is difficult for the Soviet Union to counterattack Germany alone, and the help of the United States allowed the Soviet Union to counterattack Germany and finally win.