The defining security challenge of our times is the US-China geopolitical rivalry, the intensity of which seems to be growing by the day. International relations scholars have resorted to two paradigms to describe and analyze the rivalry: the security dilemma paradigm and the power transition paradigm. Which paradigm better reflects the nature of the competition today? We argue that in recent years, the US-China competition hews closer to power transition than it does to security dilemma dynamics. Our argument is based on four “observable implications” that fit better with the power transition perspective: certainty about what “the other” is up to, indifference to the unintended consequences of one’s actions, the paucity of reassurance policies, and the adoption of full spectrum responses—encompassing military, economic, technological, and cultural dimensions—to the challenge posed by the other side.