The dynamics of Jupiter's rapidly rotating magnetosphere is dominated by the outflow of material originating from the moon Io, orbiting deep within the magnetospheric cavity. The outward radial transport of this plasma results in the breakdown of corotation at all local times, which in turn sets up a large-scale magnetosphere-ionosphere coupling current system. We have recently discovered that the main auroral emissions at Jupiter are created by upward field-aligned currents associated with this large-scale transfer of angular momentum, and we have developed theoretical models which derive the properties of the auroral primaries. This work will be reviewed for Jupiter and then extended to the kronian magnetosphere and examine whether or not the field-aligned currents associated with corotation enforcement are capable of producing the main auroral oval at Saturn, or if we expect the system to behave more like the Earth.