Levies are currently set at a blanket 10%, down from rates set as high as 49% on Cambodia and 46% on Vietnam. With the latest exemptions, the effective rate on Vietnamese goods will fall to about 7% as close to a third of its exports to America, largely technology products, are exempt.

President Donald Trump’s tariff moves are distinctively dramatic but are part of a longer-term trend. Protectionism has been growing since the last phase of the Obama administration. The administration’s Transpacific Partnership (TPP) treaty negotiations initially garnered strong bipartisan support,