Internal Security Act (Singapore) in the context of "1968 Singaporean general election"

Barisan Sosialis (BS), also known as the Socialist Front, was a left-wing political party in Singapore. It was formed on 29 July 1961 and was officially registered on 13 August 1961 by the leftist faction of the People's Action Party (PAP) who had been expelled under the leadership of Lee Kuan Yew. The prominent founding members of BS were Lee Siew Choh and Lim Chin Siong. It was one of the biggest opposition parties in Singapore during the 1960s. The main objectives of BS, in its own words, were "eradicating colonialism", establishing a "united independent and democratic Malayan nation" comprising the Federation of Malaya and Singapore and "introducing an economic system to promote prosperity and stability in society."

As the PAP consolidated its power during the 1960s, the PAP-led government cracked down on BS, accusing it of pro-communist activities as part of the geopolitical climate of the Cold War. In 1963, as part of Operation Coldstore, over 100 opposition leaders, including Lim, were arrested in preventative and indefinite detention under the Internal Security Act (ISA) with support of the British and Malayan governments. The arrests severely weakened BS, with boycotts by BS MPs to Parliament leading to more arrests throughout 1966 and 1967, most notably Chia Thye Poh. BS would fully boycott the 1968 elections, cementing PAP's political dominance. These crackdowns were justified by the government as a security measure to prevent a communist revolution; Chia himself declared that the means of the struggle would be "street demonstrations, protests and strikes". However, the political crackdowns were also criticised as political suppression, as the BS members did not publicly agitate for communism or subversion.

The 1964 race riots in Singapore were a series of communal disturbances and racial conflicts between the Malay and Chinese communities in Singapore. They occurred just months after Singapore's merger with Malaysia on 16 September 1963 and were regarded as the most serious and prolonged racial violence in the nation's post-war history. Although 1964 was marked by general racial tension, the term specifically refers to two major outbreaks on 21 July and 2 September, particularly the former, which was more severe and resulted in 23 deaths and 454 injuries.

The riots had significant political consequences and raised concerns about Malaysia's racial stability following Singapore's inclusion. Around this period, secret negotiations were initiated between the Malaysian federal government and the Singaporean state government on the possibility of separation. The events were later regarded as pivotal in leading to the independence of Singapore in 1965, shaping its national policies of multiracialism and multiculturalism. It also provided continued justification for laws such as the Internal Security Act (ISA) to monitor and curb potential incitement of racial or religious hostility.