Beijing has good reason to push Seoul to keep its doors open. The motivations are driven less by a belief in free trade and more about the emerging sectors where China is becoming a global leader, areas of South Korean industry most vulnerable to new competition.

Both sides should ¡°maintain stable and smooth industrial and supply chains¡± between them and the world, Chinese Premier Li Qiang said ahead of the recent trilateral summit that included Japan. ¡°China is ready to work with South Korea to accelerate the second phase of China-South Korea Free Trade Agreement negotiations,¡± the official Xinhua News Agency cited Li as saying.

In geopolitics, there¡¯s no such thing as free-trade absolutism. Countries pick and choose which counterparts are offered unfettered access and which have tariffs blocking their path. If leaders sense a rival may have a competitive edge, then barriers go up; the U.S. escalation of duties against Chinese electric vehicles and solar cells are one example. China hasn¡¯t been innocent either, raising import taxes on U.S. products in response to the trade war started by the Trump administration.