President Trump promised he'd negotiate a better nuclear deal with Iran than the one struck under Barack Obama, which he's described as "the worst deal ever negotiated." But after another Trump-brokered ceasefire appears to have broken down, that looks increasingly unlikely.

So what did it take to get the 2015 deal over the line? Matt sits down with former US Energy Secretary Ernest Moniz, one of its lead negotiators, to talk about negotiating with Iran, Trump's approach to diplomacy, and how worried we should be about the risk of nuclear conflict.

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Check out our series on YouTube: https://www.youtube.com/playlist?list=PLDTPrMoGHssAfgMMS3L5LpLNFMNp1U_Nq