[en] The kinetic equations for high mode number, long parallel wavelength electromagnetic perturbations are examined in the zero Larmor radius limit. The motivation is to determine the lowest order kinetic modifications to the existing MHD theory, specifically, those due to the effects of trapped particles and ion wave-particle interactions associated with compressional waves. A set of integro-differential equations is derived in this limit assuming that the electron transit frequency is large compared with the wave frequency; the ion transit frequency is allowed to be of the same order as the wave frequency. These equations are combined into a variational quadratic form which is used to show that the kinetic effects are stabilizing; the growth rate predicted by this system of equations is less than the incompressible MHD growth rate and the stability threshold is raised