Why Did Truman initiate his so-called Truman Doctrine in 1947?

The US developed the containment policy because of the belief that the Soviet Union was a neurotic and untrustworthy state that only sought to expand in communism, size and economy and US president Harry Truman, who needed to secure his own lot in political favor.
The Soviet's "obsession with security" and desperate need for buffer states and a warm-water port were misunderstood as actions taken to convert more nations into communism. Clearly, the losses that the Russians had to endure were much more than trivial and their struggle to recuperate and protect their people from future invasi…