A mechanism has been proposed for the current driven switching of a magnetic layer in a metallic multilayered structure; it is based on the excitation by the spin polarized current of multiple or "macroscopic" spin waves to simulate the reorientation of the quantization axis of the layer's magnetization. This is indeed a possible model for the switching; however here we point out that another mechanism provides the impetus for switching the magnetization at a lower current density than the multiple excitation process: the current-driven exchange coupling between magnetic layers. The equilibrium (zero current) interlayer coupling, aka the RKKY interaction, and its non-equilibrium extension induce a spin density in a magnetic layer due to the presence of another. The force, exerted on the magnetization of a layer by another due to this coupling, is confined to the surface (interface) because of its 1/(d*d) range dependence and oscillatory nature. But the main contribution of the non-equilibrium exchange interaction is non-oscillatory, and its decay is controlled by the spin diffusion length which is considerably longer than the typical thickness of spacer layers in metallic multilayers. Therefore it is this current driven coupling that provides the dominant energy term that promotes the switching of the magnetization of the layers.