Abstract Existing theories of superconductivity, including BCS, begin from observed phenomena and construct explanatory mechanisms. We invert this approach. Macroscopic electron phase synchronization is the causal layer. Superconductivity is the result. Starting from a weighted phase accumulation integral, we derive a single condition — w_∞ > w_c — from which zero resistance, the Meissner effect, critical field, and T_c scaling all follow. BCS emerges as a special case in which phonon-mediated coupling is the synchronization mechanism. The framework generates experimentally distinguishable predictions, most directly: stepwise resistance reduction in magic-angle graphene under continuous-wave terahertz irradiation at room temperature, without cryogenic cooling. We further specify a three-method experimental protocol for direct measurement of w_c as a material parameter, converting the theoretical threshold into an independently verifiable quantity.