U.S. Secretary of State Mike Pompeo departed Friday on a trip that will take him to North Korea, as U.S. disarmament demands are increasingly undermined by calls for sanctions relief and President Donald Trump's eagerness for a second summit with Kim Jong Un.

Pompeo will spend less than a day on the ground in Pyongyang on Sunday meeting with Kim and seeking to flesh out U.S. expectations for his regime to denuclearize. But his hosts will be looking for U.S. flexibility on North Korean demands to improve ties and even reach a formal end to the Korean War.

The top U.S. diplomat, who has struggled to balance optimism about North Korea's bright future with talk that Kim hasn't done enough to merit sanctions relief, finds himself increasingly isolated, not only from rivals like Russia and China, but also from South Korea — and from his own boss.