 Although the PAP leadership campaigned vigorously for a merger , the sizable pro @-@ communist wing of the PAP were strongly opposed to the merger , fearing a loss of influence as the ruling party of Malaya , United Malays National Organisation , was staunchly anti @-@ communist and would support the non @-@ communist faction of PAP against them . The UMNO leaders were also skeptical of the idea of a merger due to their distrust of the PAP government and concerns that the large Chinese population in Singapore would alter the racial balance on which their political power base depended . The issue came to a head in 1961 when pro @-@ communist PAP minister Ong Eng Guan defected from the party and beat a PAP candidate in a subsequent by @-@ election , a move that threatened to bring down Lee 's government . 
