To understand U.S. President Donald Trump¡¯s latest move to protect American solar manufacturers, it helps to follow the trail of a 32,000-kilometer trade route running through Kenya and a tiny Indonesian island off the coast of Singapore.

The route allowed companies to obscure manufacturing work done in China and Indonesia to deliver solar panels to the lucrative U.S. market without triggering tariffs, according to an analysis of trade and company data by Bloomberg News. And it was built in less than a year, quickly growing to support trade flows of more than $100 million monthly.

That kind of rapid reshuffling of global trade flows had become common in the solar industry in recent years as U.S. officials tried to crack down on what they say are unfair trade practices employed by China. In response, companies would shift production to a new country ¡ª for example to Vietnam then to Indonesia ¡ª Washington would follow with a new slate of tariffs, and the firms would seek new places, always staying one step ahead.