Is the world entering a new age of nuclear testing?

In the last 72 hours, comments from President Trump and his administration have sparked fresh debate about whether the US could – or should – resume the kind of nuclear weapons tests that were halted over 30 years ago.The current debate centres on whether Trump plans to test nuclear delivery systems, such as missiles, or nuclear warheads. The latter would be a major reversal of a long-standing policy, as the US has not tested a nuclear warhead since 1992, but it’s unclear what the plans involve.Today, Tristan speaks to Serhii Plokhy, a history professor at Harvard and author of The Nuclear Age, about what it would mean to return to an era of nuclear testing.Producers: Viv Jones, Xandra Ellin, Aron KellerExecutive producer: James ShieldMix: Travis EvansSenior news editor: China CollinsPhoto: Mushroom cloud rises during Operation Crossroads nuclear weapons test. Reuters