Containment
Communism however was seen as a threat to capitalism because the more countries that were communist the fewer places their products could be sold. So to prevent the spread of communism it must be contained and especially after WWII with many countries recovering it would be important to get them going strong so as to not switch to communism. However first WWII would need to end.
Nearing the end of WWII the allies needed to figure out how to split up Europe after the war. The "Big Three", FDR, Churchill, and Stalin met in Yalta to determine this. However it would only be until Potsdam in June 1945 that this would be figured out and Germany would be split into 4 zones and Berlin would also be split in 4 zones. This would however lead to a problem as Berlin was in the Soviet zone so they could easily cut off access to the city
And that they did. They cut off the US, GB, and France from reaching Berlin and because people living there would no longer be receiving food they needed to do something. So they sent supplies by airlift which gave citizens food and supplies. However because Stalin did not want a war he did not shoot down the planes and because he started to look back he eventually ended the blockade after a year.