Morale in Beijing, which is weary of American influence in Taiwan and the South China Sea, will be boosted by Vietnam's refusal to host foreign bases on its soil, analysts said as Vietnamese Communist Party chief Nguyen Phu Trong concluded his four-day visit to China.
During his meeting with Chinese President Xi Jinping, Trong said ties with China were the "top priority" of Vietnam's foreign policy.
He said his government sought to work with Beijing to maintain peace and stability and avoid maritime conflicts "affecting the overall development of relations between the two countries".
According to the account of the meeting released by the Chinese side, Trong told Xi that Vietnam would not allow any overseas military base to be established in the country, and nor would it join forces with any country against another.
Statements released by Vietnam did not include those remarks but said Trong had told Xi that upgrading ties with China was Vietnam's top priority. In a meeting with Chinese Premier Li Keqiang on Tuesday, Trong said Vietnam would stick to the one-China policy.
According to Song Zhongping, a former People's Liberation Army instructor and analyst, the South China Sea - which is also claimed by regional states, including Brunei, Indonesia, Malaysia and the Philippines - is an "unavoidable issue" that the socialist neighbours will have to confront eventually.
"If any problem arises between China and Vietnam, it would be over the sovereignty of the Nansha Islands because [Beijing believes] all of the islets, cays and reefs belong to them, and that Vietnam is illegally taking them," said Song, referring to the islands also known as the Spratlys.
Sino-Vietnamese relations have remained largely stable and are likely to continue to be while Hanoi maintains neutrality amid Washington's growing regional influence through the United States Indo-Pacific strategy.
"If there is any kind of conflict between China and the US in the Taiwan Strait, Vietnam will not choose to fight for either side," Song said.
"Vietnam has not formed a military alliance with any Western countries, including the US, so it will not fulfil treaties like the Philippines and Singapore do - it has no obligations."
Song said foreign use of Vietnamese ports would only occur on a case-by-case basis, because the country did not intend to permanently lease out its military bases, including Cam Ranh Bay or Da Nang.
"Hanoi is avoiding the kind of side-picking that occurred during the Cold War," he said.
The US has conducted freedom-of-navigation operations over the disputed waters and called for Southeast Asian nations to stay alert to China's military moves in the region. US ambassador to Vietnam Marc Knapper recently described Vietnam as a "true and equal partner" in apparent competition with Beijing for Hanoi's friendship.
Historical factors, including Vietnamese people's memory of the Vietnam war, are also an indication that Vietnam will not become a military ally of the US, despite the latter's recent backing of Hanoi over territorial disputes, according to Kalvin Fung Ka-shing, Southeast Asian relations researcher at Waseda University in Tokyo.
"Trong's statement helps to reassure China about its intention and aversion to forming formal alliances, especially anti-China ones, with any big powers," said Fung, referring to Hanoi and Washington's ideological incompatibility and Vietnam's "four noes" defence policy, which Trong reiterated in his speech.
Under the "four noes", Vietnam advocates not joining military alliances, not siding with one country against another, not giving other countries permission to set up military bases or use its territory to carry out military activities against other countries, and not using force - or threatening to use force - in international relations.
"This is a rather stark contrast with the Philippines' potential posture, as its ambassador to the US has hinted earlier that US forces might be allowed to use its base in case of militarised conflicts in Taiwan," said Fung, adding that Vietnam's "multidirectional" foreign policy implied it would build ties with as many powers as possible and avoid excessive dependence on one particular power.
"[Trong's statements] don't mean that Vietnam will always be standing on Beijing's side when their interests conflict, as there is still a lot of space for Hanoi to navigate without becoming a formal security ally with other major powers."
Last year, Vietnam signed a defence equipment transfer agreement for Japan to provide technology and vessels. Fung said such cooperation "strengthened" Vietnam's maritime capacity in the South China Sea. Upgraded diplomatic ties with Washington could also be expected.
According to Xu Qinduo, a senior analyst at the Pangoal Institution, a Chinese public policy think tank, it is unlikely Washington can successfully rally Hanoi into becoming anti-Beijing over the disputed waters.
"Vietnam … welcomes US support over its territorial disputes with China, but there's a limit to how far they'll accept it. After all, Hanoi understands that Washington may use them as a tool against Beijing, as it's basically impossible for Washington to truly embrace a socialist country like Vietnam," Xu said, adding that sound relationships with Asean states were benefiting Beijing.
