In early March, the UN Security Council passed Resolution 2270, sanctioning North Korea, and this resolution is indeed an unusual and remarkable document. This resolution introduced what has been correctly described as the strictest sanctions regime ever, and it was supported not only by the United States, but by all other permanent members of the UN Security Council, including China.

Frankly, this was a surprise to many observers, including yours truly. Shortly before the resolution was passed, in January and early February, I visited both Beijing and Washington and then my impression was that the Chinese – at least, until late January – had no intention to endorse really tough sanctions against North Korea. They more or less agreed that something should be done after the fourth nuclear test, but there was a near consensus in Beijing that measures should not be excessively harsh.