The common view for the substorm current system is a current wedge involving principally an azimuthal current system. We first evaluate briefly previous studies that provide strong evidence for the dominance of a meridional current system (MCS) in substorms. Based on these clues, we propose the dynamo for the MCS to be a kinetic current disruption process such that dipolarization is achieved by magnetic field line slippage, thus producing the dynamo action of a tailward directed current with an earthward directed electric field. The total current strength is estimated to be ~10 MA for an average substorm size, consistent with that obtained from the KRM algorithm.