President Donald Trump's latest confrontation with China's most important tech company may just have plunged the world into a technology cold war.

Efforts to limit the ability of Huawei to buy from suppliers reliant on American technology threaten to tie the hands of a company that aimed to become a key global supplier in the era of 5G mobile communications.

China's control of information within its borders, through restrictions on access to the global internet, had already put it in a separate digital universe to much of the rest of the world. Now, by cutting off Huawei, the US has