US government data shows it ran a $14 billion trade deficit with Malaysia in the first eight months of this year and a $77 billion trade deficit with Vietnam over the same period. Its trade deficit with Thailand was about $28 billion.

Vietnam has been “very successful” in getting firms to look to locate some or all of their manufacturing processes in the country, trade expert Deborah Elms explained.

“As Vietnam is well connected to key markets through free trade agreements, it has been an important incentive for new inward investment,” Ms Elms said.

Some of these investments are currently coming from Chinese firms looking to diversify their risks, lower production costs or avoid the high tariffs that apply to goods shipped directly from China.

“In general, this should not pose a problem. Of course, Vietnam needs to educate firms about the rules of these agreements so that firms take the right steps to legally claim origin,” said Ms Elms of the Asian Trade Centre, a trade consultancy in Singapore.

“However, if Trump is re-elected, Vietnam (in particular) could face a problem because Trump is obsessed with bilateral trade deficit figures for goods. Vietnam sends far more products to the US than the other way around and will probably want to stop that,” she added.

But US firms with sizeable business interests in and with China could exert some influence, said Dr Oh Ei Sun, senior research fellow at the Singapore Institute of International Affairs.

Tariffs and sanctions could be “routinely waived” under intense lobbying from such firms in the scenario of a second Trump presidency, he said.

“It remains to be seen whether a second Trump administration will vigorously enforce these hostile measures against China and, by extension, these tariffs and destinations that evade US sanctions in Southeast Asia,” he said.

Additional reporting by Melissa Goh