In August 1957, Singapore was still a British colony. However, earlier that year, Britain agreed to set in motion the wheels for internal self-government.
The Labour Front, helmed by then Chief Minister Lim Yew Hock, was in power in Singapore's fledgling Legislative Assembly, and the People's Action Party (PAP), led by Mr Lee Kuan Yew, in opposition.
That month, at the fourth PAP conference, pro-communists won control of the top posts in the Central Executive Committee (CEC), the party's highest decision-making body - a blow for its more moderate wing.
Such a blow that Mr Lee's name cropped up in intelligence reports by the United States' Central Intelligence Agency (CIA), in the context of a bold new development. Mr Lee might leave the PAP to start a new party with the Labour Front's Mr Lim, the CIA was told.
A source within Mr Lim's Labour Front party told the American consulate-general that Mr Lee was staying in the PAP temporarily so as to marshal the moderates "to create confusion among the leadership".
A special report compiled in the lead-up to Mr Lee's visit to the US in 1967 called the PAP's economic record "one of impressive achievement", and spoke admiringly of the programmes the fledgling government had put in place, such as low-cost housing. The agency judged that Mr Lee had "ambivalent feelings about the US, but a more positive attitude is evolving".
"Failure to regain his authority, which appears likely because of his present weakened position, may lead to his resignation at an opportune moment to help the Labour Front form a new party," read the intelligence report.
It was part of a trove of 930,000 declassified documents published online by the CIA this month. Many of its reports at the height of the Cold War were concerned about rising communist influence in Asia.
The report on the PAP, headed Communists Assume Virtual Control Of Influential Singapore Party, went on to say such an alliance would be "a logical development" for both men, given Mr Lee's loss of influence in the PAP and Mr Lim's need for a stronger political outfit.
Such an alliance would be urgent, as city council elections - the first time all seats would be open for popular voting - were a few months away, the CIA noted.
Of course, its reports were compiled from intelligence by officers in the field in various countries, with all the challenges of authenticity and motivation for such information that this might involve.
Indeed, history turned out differently: Mr Lim's government launched a series of anti-communist arrests. Among the 35 picked up in the first swoop were five of the six newly elected left-wing members of the PAP's CEC.
The arrests allowed the moderate wing of the PAP to regain control, and caused the Labour Front to lose support among the Chinese majority. The PAP went on to win 13 of the 32 seats in the city council later in December to Labour Front's four.
The agency's database of more than 12 million pages on CIA activities from the 1940s to 1990s also includes some 28,000 pages of declassified presidential briefs from the Nixon and Ford administrations.
Historians told The Straits Times that the CIA assessments have stood the test of time, and provide insights into what the US thought was important to know of Singapore and the world, and also how that information was processed into assessments and used in policy briefs.
"They show that the CIA 50 years ago was well informed about politics in Singapore, and able to make perceptive judgments about Lee Kuan Yew and how he was defining Singapore and its policy dilemmas," said Mr Kwa Chong Guan, senior fellow at the S. Rajaratnam School of International Studies. "There is not much to disagree with in these assessments even today."
The period leading up to the separation from Malaysia was covered in some depth in presidential briefs.
"A sharp new confrontation looms between the central government in Kuala Lumpur and authorities in Singapore," read a June 1965 brief foreshadowing the split.
"Singapore leader Lee Kuan Yew threatens to push matters to the point of a partition of Malaysia unless Prime Minister (Tunku Abdul) Rahman breaks with his more extremist Malay followers. These elements, in turn, are demanding strong actions against Lee," it said.
The CIA files also hint at how American leaders' view of Singapore and Mr Lee - and vice versa - gradually evolved as the island proved to be a viable nation.
A special report compiled in the lead-up to Mr Lee's visit to the US in 1967 called the PAP's economic record "one of impressive achievement", and spoke admiringly of the programmes the fledgling government had put in place, such as low-cost housing.
The agency judged that Mr Lee had "ambivalent feelings about the US, but a more positive attitude is evolving".
Part of this boiled down to increased US commitment in Vietnam, which Mr Lee hoped would prevent communism from spreading further into South-east Asia.
"US policies in South-east Asia have a significant bearing on his own aspirations for Singapore, particularly his need for time to build a stable, cohesive society," said the report.
It added: "The pragmatic prime minister is also aware that about 15 per cent of Singapore's national income derives from US procurements in Singapore for Vietnam."
Later files showed that US presidents were eager to tap Mr Lee's views as they formulated American policy towards Asia.
Among the questions Richard Nixon asked him during his 1973 visit to the White House were what the US should do in South-east Asia, his views on Japan and Indonesia, and whether the US was pursuing the correct policy towards China.
At one point, Mr Lee was cited telling President Nixon: "Americans cannot go on being self-pitying. A weak America is dangerous for the world."