Huawei has hit back against US allegations that it poses a national security threat, as the FCC proposes further restrictions on the contracts the Chinese firm can chase in the US. The subtext, of course, is fear that the authorities might try to go even further and limit Huawei’s ability to buy components from US firms. That sanction was already imposed on ZTE, and although it seems likely that a compromise will be reached, the draconian threat – which would hit US vendors like Qualcomm and Intel as well as Chinese buyers – has set a precedent that many find disturbing. Although it is less dependent than ZTE on US-made components – it has its own chip subsidiary and a…