In boardrooms and backstreets from Singapore to Hanoi, owners of Asia’s small and medium-sized enterprises had barely got over the shock of the pandemic’s economic upheaval when another disruption arrived – this time from Washington, in the form of new tariffs that risk upending cross-border commerce and livelihoods.Following a series of hard-fought trade negotiations with the Trump administration, many Southeast Asian nations now find themselves confronting US tariffs ranging from 19 to 20 per...