It can quickly become a national security concern when you realize the people making the chips have total control over the systems built with them. Modern computing is built around the idea of "trusted computing" where certain pieces of hardware control the root of trust. There's also plenty of issues with backdoors (lookup intel ME if you're not familiar). The ability for the US to maintain its backdoors into foreign computing systems and preventing China from gaining that ability is the same cold war crap but in the cyber rather than the economic domain.