I disagree. Tillerson was simply making it clear that the US will not tolerate Chinese expansionism in the South China Sea (much the same as China did when the UN invaded North Korea). The comparison of the US with bygone imperial powers is very questionable given the US has no colonies that it it administers or has to protect. This issue relates to freedom of navigation in the area for all nations and the concern that the Chinese intend to limit such freedom is quite legitimate. The US naval power is far superior to that of the Chinese and they have the capability to 'budge' the communist's from these islands if free passage of the area is impeded. Like Korea, a confrontation is not likely to lead to 'global war' given the scenario of mutual assured destruction still exists and Chinese leaders, like most others, are not wont to perish in a nuclear exchange.