‘Frenemy’ China remains vexing campaign test for US presidential candidates Donald Trump and Hillary Clinton

It doesn’t rival Islamic State or abortion as an issue in the presidential race, but China might be the most complex challenge the winner will have to deal with.
The country, which has the world’s second-biggest economy and second-highest military spending, is a frenemy of the first order.
It finances America’s federal budget deficit by buying Treasury bonds, and it sends more students to the US than any other nation. It’s a natural ally on some issues (Islamic terrorism) but an implacable foe on others (freedom of navigation in the South China Sea).

President Barack Obama will bequeath his successor a string of partial successes. China, the biggest greenhouse gas polluter, agreed with the US to curb emissions, albeit not as fast as the administration would like. It allowed its currency to gain in value, making its exports less competitive — although lately the yuan has fallen again.
China didn’t retaliate after the US Navy cruised by contested islands in the South China Sea in October, but the country’s Ministry of National Defence didn’t hesitate to accuse Washington of a “serious military provocation” on December 19, days after a pair of B-52 bombers flew over Chinese-built artificial islands in the same area.