Existing models of membrane instability and breakdown under an applied voltage are critically examined. An alternative, speculative treatment of the electroelastic model is suggested, based on the assumption that spatial dispersion of the elastic moduli leads to their effective softening at short wave lengths. The model parameters that account for these effects are chosen to ensure that short wave length thickness fluctuations become unstable at moderate applied voltages, similar to 1-1.5 V. With these parameters we treat the membrane stretching diagram and membrane thickness fluctuations. The stretching diagram agrees with experimental findings and earlier calculations. Computed thickness fluctuations are consistent with previous investigations.