“I was surprised by the Chinese side’s focus on survivability, on ensuring that it has a second-strike capability,” said the smart young Chinese security specialist with whom I was chatting.

That statement caused me to lean back, myself surprised at this assessment of the previous two days of discussion. My interlocutor should have known — should have been brought up on the notion — that China is a vulnerable state, subject to blackmail whenever it is weak or perceived as threatening. Those moments in the U.S.-China relationship when Washington played the nuclear card against Beijing and it was unable to respond have burned themselves into China’s collective consciousness: Never again!

My young Chinese friend was right, though. At the heart of China’s nuclear policy is a search for a guaranteed retaliatory capability, the confidence that its nuclear weapons will survive a U.S. first strike and be available to punish the U.S. in return. “Assured retaliation” is China’s insurance policy, a rejoinder to U.S. attempts to threaten, blackmail or deter Beijing.