What caused suspicious between the united States and the Soviet Union During World War 2?

Answer 1

Partly the distrust was due to Stalin's personal paranoia. Stalin trusted no one. The one and only person he ever brought himself to trust was Adolph Hitler, when they were partners in crime, each merrily invading his neighbors between 1939 and 1941. And then his buddy Hitler stabbed him in the back and invaded Russia.

There was a more concrete reason for the distrust though. Both the US, and to a greater extent the UK had sent military forces to Russia just after WWI ended, to try to help the "White Russians" beat the Reds, the communists, of whom Stalin was one, and who nevertheless held on and eventually were able to consolidate their control over Russia. So the US and the UK were unsuccessful in strangling the communist revolution in Russia in the crib. But they had continued to be vocal in denouncing communism in general and the Soviet Union in particular. The Russians had never forgotten this.

Answer 2

As with a lot of evil things it began with Stalin's paranoia. Some in the US really thought that the soviets were building an industrial state with good will. Uncle Joe had been cheerfully murdering and starving millions. Some claim he personally murdered many of his own family. There is fairly strong circumstantial evidence of this.

Stalin hated the Poles and thought that Churchill was trying to trick him into war with Hitler. Churchill probably would have as he wanted the US and the USSR to strike at the Germans to preserve the British Empire.

The US and Britain were supplying some of the USSR's war materiel. From the time it became possible that the allies would win Stalin drove a tough bargain to divide Europe up very much in favour of the USSR as he wanted many buffer states between Russia and the USSR. Uncle Joe wanted a second front by the allies long before it happened and the USSR undoubtedly had the greatest losses from bearing the brunt of the Nazi war machine effectively alone. Hitler thought he would 'kick in the door of the Soviet Union and the whole rotten thing would fall apart'.

The only powers that mattered from 1943 on were USA Russia and Britain in that order and Stalin distrusted the allies with clinical level of paranoia. On the US side Patton was literally a loose cannon and it could be argued that only the steadfastness of Roosevelt Truman and Eisenhower stopped WWII from segueing into WW III. Stalin knew he was weak but acted tough up to his death in 1953.

That is the short answer but the reality is a lot more complicated.

Answer 3

they were getting suspicious about each other because the united states and the soviet union had some tense relations before WWII with their different political system.