The virtual summit of the Association of Southeast Asian Nations taking place this Friday presents a challenge -- not only for the 10-nation bloc but also for Vietnam, the group's 2020 chair.

Without the backroom chats for all-important consensus building -- ASEAN's key measure of success -- the summit, delayed for nearly two months by the COVID-19 pandemic, demands a new style of diplomacy from Vietnamese Prime Minister Nguyen Xuan Phuc. He will have to negotiate online instead of in person in the port city of Da Nang, the original venue.

The format might not matter if ASEAN had developed a tradition of strong leadership, perhaps from its largest or best-run member countries. This model was shunned by the bloc's founders to promote equality among the group's diverse membership, but in recent years it has developed into a serious institutional weakness. Now it must deal with this problem.

Indonesia has at times been seen as a de facto leader because of its size. However, Jakarta has shied away from exercising its inherent authority since the election of President Joko Widodo, whose focus on domestic policy has left a regional leadership vacuum.

There are few other national candidates for Southeast Asian leadership. The Philippines under President Rodrigo Duterte has abandoned any attempt to challenge Chinese territorial assertiveness, choosing instead to cozy up to the regime of President Xi Jinping. Malaysia and Brunei, whose territorial claims also conflict with those of Beijing, have become reticent in the face of Chinese aggression, while Thailand and Singapore have sought largely to avoid jeopardizing bilateral ties with China.

As a latecomer to ASEAN, having joined in 1995 -- nearly three decades after the organization was founded -- Vietnam has been disinclined to take up a leadership position, despite rapid economic progress and encouragement from some other member states.

At the outset of its membership the country's economy lagged behind the six existing ASEAN members, and it was grouped with other latecomers in a second tier known as CLMV -- Cambodia, Laos, Myanmar, Vietnam. But the subsequent quarter century has seen impressive growth, with Hanoi thriving despite the recent impact on the region of the U.S.-China trade war.

Vietnam is seen to have performed strongly in the fight against COVID-19, earning respect for its impressive suppression of the disease from wealthier and more developed member states such as Singapore, Thailand and Malaysia.

The country remains economically less developed than many other ASEAN member states, but is poised to minimize the economic hit from COVID-19, recovering faster from the post-pandemic global recession and adapting to new opportunities better than most of its neighbors.

It has proved a capable host in previous stints in the ASEAN chairmanship, which rotates annually, but has not tried to lead ASEAN in every respect, rather picking security and diplomacy. It has no desire to replace Indonesia as the organization's de facto leader, and will not do so.

As a prime target of Chinese expansionism Hanoi has taken up a pivotal role in conflict management in the South China Sea, emerging as the region's front-line defender of the territorial status quo and demonstrating its interest in investing more diplomatic capital in the regional body. Importantly, Hanoi has shown strong support for ASEAN's institutional relevance in the region, unlike some bigger and better resourced neighbors with longer tenure in the organization.

For all these reasons, Vietnam's fellow ASEAN members appear confident of Hanoi's diplomatic capability, even in the trying circumstances of an online and relatively underprepared summit.

Hanoi's example points to a way out of the leadership conundrum for ASEAN -- if the organization is to prosper and develop it needs other member states to take active leadership roles in specific sectors of ASEAN activity.

ASEAN has transformed Southeast Asia since its foundation in 1967. But external conditions are changing again as the acrimonious trade and security relationship between Washington and Beijing sours the regional diplomatic environment.

Against this background Nguyen will do well to hold the ASEAN line on the South China Sea on Friday, and even better to maintain the organization's facade of consensus in the face of widely diverging views on the region's future.

Whatever the outcome of the virtual summit, however, the group needs to come to terms with the fact that no single member can restore its diplomatic centrality. That requires a collective effort of the willing and the committed.