Upon re-examining the characteristic polarization angle sweep of rotation-powered pulsars, we find that the sweep is perceptibly shifted by aberrational effects and by polar-cap current flow. In addition to the previously known phase shift of the entire sweep by ΔΦ = −4r/RL , aberration shifts the polarization angle itself by ΔΨ = −(10/3)(r/RL ) cos α. Similarly, current flow above the polar cap shifts the polarization sweep by ΔΨ = (10/3)(r/RL )(J/JGJ ) COS α, potentially providing a method of directly measuring the magnitude of the current. The competition between these two effects produces a potentially observable signature in the polarization angle sweep.