The Missing Action: A Variational Foundation for Normative Field Theory: Euler-Lagrange Dynamics, Gauge Transport, and Dissipative Constitutional Lock-in in IusSpace

Normative Field Theory (NFT) models legal systems as trajectories on IusSpace, a twelve-dimensional differentiable manifold whose metric depends on constitutional lock-in, institutional hysteresis, and subsystem modularity. Its existing formulation defines a normative metric tensor, a non-Abelian gauge connection, holonomy, and a phenomenological force ratio, but it does not specify an action functional from which institutional trajectories can be derived. This paper supplies that missing variational layer. It defines an extended configuration space containing institutional position, professional-prior orientation, and internal residue variables; proposes a conservative action combining metric kinetic cost, meme-induced potential, internal-memory energy, and Yang-Mills curvature density; and derives the corresponding Euler-Lagrange equations. The published phenotypic-force ratio cannot arise as a conservative force from stationary action alone because its denominator functions as impedance and its hysteretic component is dissipative. Dissipation is represented by the constitutive family Gamma(varrho,d,q) = eta(varrho) chi(d) H(q), with H symmetric positive semidefinite. The ratio is recovered as a separable factor only under a declared calibration in the overdamped limit of a Lagrange-d'Alembert system. An executable SymPy audit tests representative reduced-dimensional scopes: two institutional coordinates, SO(3) for the prior-vector force, and SU(2) for commutator and covariance checks. Dimension-independent analytic arguments explain extension under stated assumptions, but the executable run is not itself a twelve-dimensional U(2) verification. Generic path-ordered transport and dimensional closure remain unconfirmed. No new empirical validation is claimed. Verification scope. The executable files accompanying this record implement representative two-dimensional, SO(3), and SU(2) checks. They must not be described as a direct twelve-dimensional U(2) verification. This paper is a formal-derivation companion to Normative Field Theory (Zenodo 20779167) and forms part of the Law as Extended Phenotype research program.