Let X be a smooth complex projective variety and let α ∈H2p(X,Q)∩Hp,p(X) be a rational Hodge class. We prove that α is algebraic. The argument proceeds by reducing algebraicity to the vanishing of a canonically defined primitive residual defect. The key local step is a comparison theorem identifying the singularity contribution of an admissible normal function with the specialization class of a relative cycle along a semistable boundary, and hence identifying the corresponding local multiplicities. Summation over the boundary components then forces the global residual class to vanish, which yields the collapse of the primitive defect. A second ingredient is the realization step: fiberwise algebraicity is converted into the required relative realization through properness of the relative Chow space, finiteness of irreducible components, constancy of the cycle class on a dominating component, generic-point spreading, and admissible closure. Combined with the monodromy and evanescent exclusion package, this yields the main theorem.