Resistive ballooning mode stability is examined using one-fluid, two-fluid, and kinetic theories to determine the domain of validity of the resistive-fluid theories in the high-beta Doublet III tokamak. In general, it is found that the requirements for the validity of the resistive-fluid theories in Doublet III are only satisfied on the cold, outermost edge of the plasma with temperatures T ≤ 25 eV. In the domain of validity, the two-fluid and kinetic theories are qualitatively the same and indicate that the dominant effect is parallel resistivity with small corrections from perpendicular resistivity, fluid compression, thermal conduction, and ion collisional viscosity. The generic role of resistive ballooning modes in tokamaks and the implications for anomalous transport are also discussed.