The Axe Files, featuring David Axelrod, is a podcast distributed by CNN and produced at the University of Chicago Institute of Politics. The author works for the podcast.

Washington (CNN) The mounting threat posed by North Korea will require high-stakes diplomacy at a time when America's credibility is weakening around the world, says Wendy Sherman, a former US diplomat and lead negotiator of the Iran nuclear deal.

"(Kim Jong-un) fundamentally believes the only way he survives is to have nuclear weapons," Sherman told David Axelrod on "The Axe Files," a podcast from the University of Chicago Institute of Politics and CNN. "The world has to show him that it is a choice between those weapons and survival."

Noting that the North Korean leader might use nuclear weapons "if he felt his back was up against a wall," Sherman warned that the failure to come to a diplomatic solution could risk a catastrophe of "unimaginable" consequences.

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