The U.S. should learn from the Norks – start a program of pin-prick territorial infringement that is brazenly denied, then escalate and de-escalate to taste.

For example, recycling Cold War practice, resume balloon drops of cash (U.S. $ or Chinese Yuan) and propaganda aimed at North Koreans, especially aimed in remote areas. Use cheap UAV’s for more targeted drops of goods (including weapons) aimed at North Korea’s concentration camps.

Catalog the North Korean population, then use small bribes to communicate through indirect channels deep into North Korean society, especially outside Pyongyang.

For example, a reward could be offered whenever complementary messages reach a single recipient inside North Korea through different channels. The recipients would not necessarily need to know exactly what triggers the reward – only that passing on communications can pay.