Condoleezza Rice

Tough talk: US envoys on how to negotiate with North Korea

President Donald Trump's Singapore summit with Kim Jong Un may be unprecedented, but during a quarter-century of on-off nuclear talks with North Korea, U.S. officials have learned a thing or two about dealing with an inscrutable adversary and have tried many tactics to get their way: quiet persuasion, black humor and even walking out of the room.

Across the table, they've faced dogged North Korea negotiators who launch into anti-American tirades, reflecting a doctrinaire mindset and the vast ideological gulf between two nations still technically at war. But they've also encountered officials who are polite, know their brief inside-out, and occasionally flash wit.