In a nutshell, the Truman Doctrine, containment and Marshall Aid were all aspects of the same 1948 US foreign policy that was concerned with preventing the spread of Communism in Western Europe by peaceful means.
The policy was drawn up in haste following WWII given the real possibility that Communism could spread to Western Europe, which the Allied Forces saw as a threat to world peace. If you’re wondering how on earth the situation could have gotten so dire, you’re in luck because we have the answers!
Things got this bad because resistance to the occupying Nazi German forces in WWII had often been organised by Communist groups and these hoped to achieve power in the post-war world. The British intervention in Greece to prevent a Communist takeover was a good example of this. Additionally, social disruption and damage to infrastructure meant many people in Western Europe faced a bleak future at the end of the war. So, the US and Britain feared that some Western European countries would turn to Communism as a political solution in the post-war elections. This is where the European Recovery Plan – or Marshall Aid as it’s best known – came in.
Then-US President Harry Truman believed that Communism could be contained and that this was a better form of confrontation than an outright war. To this end the countries of Europe were offered Marshall Aid to help post-war recovery. The plan, nicknamed after George Marshall, the then-US Secretary of State, provided huge amounts of money to aid the recovery of Europe after WWII.
While Marshall Aid did a great deal of good for Western Europe, it wasn’t able to help the Soviet satellite states at all because Soviet leader Joseph Stalin refused to allow the countries of Eastern Europe to accept it. This was because he viewed Marshall Aid as a form of American economic imperialism.