In specific cases, the critical beta (βc) for stability against internal magnetohydrodynamic (MHD) ballooning modes can be improved significantly by taking into account the stabilizing influence of the ion diamagnetic drifts. This kinetic modification to the ideal MHD analysis and radial corrections to the local theory are included in a calculation of βc as a function of toroidal mode number (n) for a particular tokamak equilibrium sequence of interest.