Yet China has no interest in a failed or existentially weakened North Korea, which it needs as a buffer against U.S. ally South Korea. And there is no prospect of changing this Chinese incentive.

Trump talked a big game on China during his presidential campaign — and has delivered nothing, diplomatically speaking. Tillerson offers a correct diagnosis of the problem: “China’s rise as an economic and military power,” he writes, “requires Washington and Beijing to consider carefully how to manage our relationship for the next 50 years.”

In other words, the cool war between the U.S. and China is continuing. 1 But the Trump administration, including Tillerson, has taken no visible steps to figure out how that cool war should be shaped.