I was a bit surprised by this news because it was only a few years ago that Stephen Bosworth was the key person in the Obama administration making North Korea policy:

Stephen Bosworth

Stephen Bosworth, a long-time Korea expert who served as U.S. ambassador to South Korea and as Washington’s special representative for North Korea policy, has died. He was 76.

Bosworth died at his home in Boston on Sunday, according to Johns Hopkins University’s School of Advanced International Studies. Bosworth had served as chairman of the U.S.-Korea Institute at SAIS until recently. SAIS did not give the exact cause of his death, but the former diplomat suffered from prostate cancer.

Bosworth served as Washington’s top envoy to South Korea from 1997-2001 and special representative for North Korea policy from 2009-2011. He also served as executive director of the Korean Peninsula Energy Development Organization from 1995-1997.

KEDO was set up to implement a 1994 deal with North Korea under which the communist nation promised to freeze and then ultimately dismantle its nuclear program in exchange for energy-producing light water reactors and other concessions from the U.S. and other partners.

That deal later fell apart as the North was found to have run a clandestine uranium-enrichment program in violation of the agreement.  [Korea Herald]

You can read the rest at the link, but condolences to his family.