So now, about 39 years after defeating the Americans, why does the Socialist Republic of Vietnam want to use the Saigon regime's claim to create trouble in the South China Sea? Aren't the current Vietnamese leaders betraying Ho Chi Minh and other freedom fighters, profaning the sacrifice of hundreds of thousands of their compatriots who laid down their lives to resist foreign aggressors, and negating the valued support of their allies in the battle against colonialism by citing the comprador Saigon regime's claim?

The Vietnamese government must not violate the principle of estoppel in the Xisha and Nansha islands' sovereignty issue. Vietnamese leaders claim that no country recognizes that the Xisha and Nansha islands belong to China. This is a brazen lie, because the Democratic Republic of Vietnam topped the list of countries that accepted China's sovereignty over the islands.

The Democratic Republic of Vietnam's position was unequivocal in the 1950s and 1960s. The position remained unchanged even after the death of Ho Chi Minh and the end of the Vietnam War in 1975. Documents with the Chinese Foreign Ministry from the 1970s and 1980s show the position of the Ho Chi Minh-led Vietnamese Communist Party on the Xisha and Nansha islands. The most important of these documents is a note given by former Vietnamese premier Pham Van Dong to Zhou Enlai and the declaration of the Democratic Republic of Vietnam in 1965.

On Sept 4, 1958, the Declaration of the Government of the People's Republic of China said that the breadth of the territorial sea of the country shall be 12 nautical miles and that this provision should apply to all territories of the PRC, including all the islands in the South China Sea. On Sept 14, 1958, Pham Van Dong solemnly stated in his note to Zhou Enlai that Vietnam recognizes and supports the Declaration of the Government of the PRC on the country's territorial sea. On Sept 22, 1958, the diplomatic note was publicly published in Nhan Dan, the official newspaper of the Vietnamese Communist Party.

On May 9, 1965, the Democratic Republic of Vietnam issued a statement on the US' definition on the "theater of war" in Vietnam. The statement said that by defining the whole of Vietnam and the waters up to 100 nautical miles off its coast as well as part of the territorial sea of China's Xisha Islands as the operational area of the US armed forces, Lyndon Johnson, then US president, has directly threatened the security of the Democratic Republic of Vietnam and its neighbors.

In recent years, however, some Vietnamese government officials and "scholars" have tried to "reinterpret" the two government documents, only to end up making fools of themselves. And after their attempts failed, the Vietnamese government started pretending as if the two documents never existed.

Vietnam has said that it is fully prepared with historical and legal evidence to prove its claim in the South China Sea, and it is waiting for the appropriate time to take China to the international court of justice. If that is so, then Vietnam should not forget to attach Pham Van Dong's note and the Democratic Republic of Vietnam's statement, as well as the maps and textbooks published by Vietnam before 1975, with its complaint.

The author is a researcher with the Research Center of World Issues, affiliated to Xinhua News Agency.