The warning to Vietnam this week from a PLA navy general who said it would regret its naval engagement with the US and would ultimately be sacrificed as a pawn by Washington will come as no surprise to Hanoi. Vietnamese officials have been bracing for months to face Beijing's displeasure at its suddenly successful campaign to internationalise South China Sea disputes - a move designed to limit China's growing assertiveness in the area. The question now is just how rough will Beijing get? As for being a sacrificial pawn in a wider Sino-US power play, that is an old fear among Vietnamese officials; Vietnam's internationalist foreign policy in recent years is based on such suspicion. Since emerging in the early 1990s after years of isolation following the end of the Vietnam war and the occupation of Cambodia, Hanoi has courted relationships far and wide but has avoided becoming beholden to any large power. To that end, the increasingly complex Sino-US-Vietnam relationship bears close scrutiny - it is one that increasingly defines the region's challenges. If China, as many diplomats and analysts across Southeast Asia now believe, has displayed premature overreach in its recent assertiveness, then it is the US-Vietnam relationship that provides the yardstick to measure that excess. The unprecedented, if limited, naval drills between the two former enemies now under way off Danang - the closest Vietnamese port to the Paracel islands, occupied by China but claimed by Vietnam - are no accident. While the timing and the presence of the aircraft carrier USS George Washington seems geared to sending a strong signal to Beijing, the drills reflect a military relationship that has been intensifying for several years, part of normalised ties that are just 15 years old. Vietnamese officials were flown out to a carrier off Vietnam's southern coast a year ago, and earlier this year a US ship was repaired at a Vietnamese shipyard close to the strategic Cam Ranh Bay - both trust-building efforts that point to a blossoming relationship. Where will it all go from here? Probably quite far. Both Hanoi's and Washington's interests are served by closer military ties and Pentagon insiders already refer to it as a strategic partnership along the lines of older friendships with Indonesia and Malaysia that are also being re-energised. There will be limits. It is hard to imagine Vietnam ever being a formal US ally for a variety of reasons, including the warning issued this week. Vietnamese Defence Minister General Phung Quang Thanh outlined Vietnam's military diplomacy in a landmark speech to a conference in Singapore last year. That diplomacy, he said, was integral to Vietnam's 'vigorous integration into the international community'. 'We advocate neither joining any military alliances, taking side with one country against another country, nor giving permission to any foreign countries to have military bases in Vietnam,' he said - a mantra widely repeated among Hanoi's military and diplomatic elites. His words were a reminder that Hanoi has relied on a range of military relationships, including its chief weapons supplier, Russia, and India, while also boosting ties with Washington. If there is still some way for the relationship to develop - keep watch for a formal deal to service US ships in Vietnamese ports - the pace and intensity may well be set by any further assertiveness by China. In that regard, Hanoi's own relationship with Beijing is a key factor and Vietnamese officials describe it as their most complex and important relationship. Despite ancient mistrust and suspicion, ties have been solidly improving for some years. The number of political, economic, security and cultural delegations increases yearly. As two of history's last Communist Party-ruled states, Beijing and Hanoi have a lot to talk about, with Vietnam learning from China's economic reforms and Vietnam's political and social reforms being watched in some quarters in Beijing. Long-simmering disputes involving the 1,400-kilometre land border and Tonkin Gulf have been settled. But, as recent events have shown, any closeness will be matched by an ever-ready hedge. That juggling act was brought into sharp relief as Vietnam hosted the annual Asean security forum last month. Foreign Minister Yang Jiechi's meeting with Vietnamese Communist Party chief Nong Duc Manh was given pole position by Vietnam's state media under the banner 'Party leader affirms VN's priority on ties with China'. Underneath, however, was a telling story about US Secretary of State Hillary Rodham Clinton meeting Prime Minister Nguyen Tan Dung. Asean together with the US, Dung said, would 'work to guarantee regional security'.