How will Beijing's controversial national security law for Hong Kong affect US-China trade relations, now that US Secretary of State Mike Pompeo has declared Hong Kong 'no longer autonomous'? Finbarr Bermingham brings political economy editors Zhou Xin and John Carter together to discuss the possible outcomes, while Su-Lin Tan looks at China's decision to massively increase tariffs on Australian barley and the potential for switching to American suppliers - is this a new front in China's trade…