China tops the list of security threats to the United States and has the potential to change the world order for “good or ill”, a senior US defence official said on Saturday. Speaking at the annual Aspen Security Forum in Colorado, John Rood, undersecretary of defence for policy, said China was “the one country, the largest country, with the ability to change our way of life in the United States, and change the global order, for good or ill”. China figured heavily during the four-day meeting of top US officials and policy leaders, which ended on Saturday.