The scale of a phenomenologically successful charge-symmetry-violating nucleon-nucleon interaction, that attributed to meson exchange with a ∆I = 1 rho-omega transition, is set by the Coleman-Glashow SU (2) breaking tadpole mechanism. A single tadpole scale has been obtained from symmetry arguments, electromagnetic meson and baryon measured mass splittings, and the observed isospin violating (∆I = 1) decay ω → π + π − . The hadronic realization of this tadpole mechanism lies in the I = 1 a 0 scalar meson. We show that measured hadronic and two-photon widths of the a 0 meson, with the aid of the Vector Meson Dominance model, recover the universal Coleman-Glashow tadpole scale.