US security alliances in the Pacific are quite robust. You can easily find some wonky articles attesting to this in greater detail. I found one from 11/23 in Foreign Policy pretty quickly.If China decides to move on Taiwan or Japan, who is stopping them?
I’m also a firm believer that economic alliances build strong security alliances. Shame the US withdrew from the Trans Pacific Partnership that intended to unify smaller regional economies and act as a bulwark against Chinese economic dominance in the region.