As Raja set to work preparing for the coming Anson byelection due on 15 July 1961, his name was being bandied about among top communist circles in Peking as a candidate for another sort of campaign — the Communist plot to subvert merger.

Since the first week of June, Chin Peng, secretary-general of the Malayan Communist Party (MCP) had been in Peking to discuss developments with the Communist Party of China (CPC). Deng Xiaoping, the secretary-general of the CPC, was convinced that the Southeast Asian region would soon be ripe for communist domination and pressed Chin Peng, a ruthless guerilla fighter who had spent many years in the jungle, to revert to armed struggle. Deng promised that China would fund the MCP's insurgency. Enthused by the prospect of eventual communist domination in the region and the ready access to funds, Chin Peng fell in line with China's wishes.

It was against this strategic backdrop that Chin Peng summoned Eu Chooi Yip, who controlled MCP operations in Singapore from his base in Indonesia, to Peking. Together with Siao Chang, a senior MCP Politburo member based in Peking for more than six years, they discussed the strength of the Singapore underground and the Tunku's bombshell announcement on merger.

At that critical meeting, they decided to sabotage the merger plan, or at least to delay its implementation for as long as possible. They were fearful that, once Singapore joined Malaya, the communist network on the island would be smashed. Between the three, a strategy was hatched — exploit the internal weaknesses of the PAP.

Chooi Yip told Chin Peng that the PAP was being split three ways, exposing its political vulnerabilities. According to Chin Peng's account, Chooi Yip argued strongly that “there was an ever widening split between the PAP's right-wing faction, led by Lee Kuan Yew, and a middle-of-the-road group, seemingly headed by Sinnathamby Rajaratnam”.