The Vietnam War took a surprise turn when the 1964 Race Riots in Singapore inspired Western politicians to pool their efforts in the region to balance rising Soviet-aligned powers. A plan was hatched to form a Southeast Asian variant on the EU, a personal union between South Vietnam and Kampuchea, intended to contain the Domino Effect in Southeast Asia with a Right-Wing puppet regime.
The new nation, known on paper as the KSV Project for "Kampuchea-South Vietnam," would become the core of the Khmer-Singapore Confederation, or more commonly, the KSC. This nation would dominate trade through the Strait of Malacca and into the South China Sea in alliance with Singapore, generating considerable wealth domestically. A plausibility study was done, but the project was shelved until the end of the US withdrawal.
Immediately following the Khmer Rouge victory in 1975, skirmishes erupted between their troops and Vietnamese forces. The Khmer Rouge immediately began supporting South Vietnam, which would have fallen by the end of April had it not been for the aid. Saigon fell under joint Khmer/South Vietnamese administration as troops from Non-Aligned nations began sending their own aid to assist in the struggle. Nationalism in both entities was an issue, but survival trumped resentment toward one another.
In South Vietnam, the war was eventually fought to a standstill as Khmer and other allied troops poured into South Vietnam and helped force a settlement by capturing Ho Chi Minh. Following the first peace talks, the Viet Cong launched a surprise attack on Coalition positions, but were swiftly repelled. In the ensuing chaos, a military officer known only as "the Grand Dragon" seized power in South Vietnam and declared a personal debt owed to the Khmer Rouge for saving South Vietnam. A surprise military genius, he managed to convince the Chinese to fly bombing raids over North Vietnamese cities so as to have a better position at the negotiating table.
Eventually the Khmer Rouge pushed the NVA forces back up to the old border between North and South Vietnam. A ceasefire was signed between the two and both sides entered a state of armed peace. Democratic Kampuchea aligned itself with the west, although nominally remained neutral.Kampuchea also pledged its support to Singapore, inherited from a joint agreement between Singapore and South Vietnam that was instated when the 1964 Race Riots occurred.
In 1987, when the Singaporean government launched Operation Spectrum to uproot a supposed “Marxist Conspiracy,” Kampuchea and the Singaporean government sought to use this conspiracy as a pretext to “unite against revisionist communism”. The Khmer-Singapore Confederation was declared January 1, 1988. Singapore's economic model was exported to Kampuchea and over the 1990's would boost the struggling economy. In return, the military protection offered by Kampuchea helped protect Singapore against potential aggressors.
As it developed as a regional power during the 90's, the US would embrace the KSC and offered an open and mutually beneficial foreign policy in exchange for liberalization governmentally, something the KSC abided by.
But it would also grow into a pariah state, slowly cutting its links with the Western powers after the Cold War ended, as it grew quickly into a prosperous rogue state. It would push forward a Third Way bloc of any nations in need of a patron against regional adversaries, funneling cash into their pockets, as well as supporting separatism and violence in Indonesia so that people would continue using the Strait of Malacca the KSC depended on for its wealth. KSC and Burma signed the Treaty of Kampong Cham in 1997, forming an alliance colloquially known as the "Alliance of Misfit Toys", to pool their collective resources toward development projects, one of which included a clandestine nuclear program.