三个世界
Following the death of Mao Zedong and the take-over in China by Deng Xiaoping, the party strongly denounced the new line of the Chinese leadership. In 1978, Party, led by N. Sanmugathasan, issued a public statement in defiance of the decision of the Central Committee not to accept the decision of the Tamils self-determination and reject the Three Worlds Theory. This decision led to a split with Tamil self-determination and TWT defenders, and many, including Samal De Silva, K.A. Subramaniam, S. K. Senthivel, S. D. Bandaranayake left the party and formed a new political party called the Communist Party of Sri Lanka (Left).