President Donald Trump reportedly asked a foreign policy expert three times why the US can't use nuclear weapons during his presidential campaign.

While world leaders may have been right to criticise Trump's line of questioning amid global promises to reduce nuclear stockpiles, why are world nuclear powers expanding and updating their arsenals instead?

In this week's Reality Check, Mehdi Hasan exposes the hypocrisy of the global nuclear elite.

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Source: Al Jazeera News