The latest cosmological N -body simulations find two intriguing properties for dark matter haloes : ( 1 ) their radial density profile , \rho , is better fit by a form that flattens to a constant at the halo center ( the Einasto profile ) than the widely-used NFW form ; ( 2 ) the radial profile of the pseudo-phase-space density , \rho / \sigma ^ { 3 } _ { r } , on the other hand , continues to be well fit by a power law , as seen in earlier lower-resolution simulations . In this paper we use the Jeans equation to argue that ( 1 ) and ( 2 ) can not both be true at all radii . We examine the implied radial dependence of \rho / \sigma ^ { 3 } _ { r } over 12 orders of magnitude in radius by solving the Jeans equation for a broad range of input \rho and velocity anisotropy \beta . Independent of \beta , we find that \rho / \sigma ^ { 3 } _ { r } is approximately a power law only over the limited range of halo radius resolvable by current simulations ( down to \sim 0.1 % of the virial radius ) , and \rho / \sigma ^ { 3 } _ { r } deviates significantly from a power-law below this scale for both the Einasto and NFW \rho . The same conclusion also applies to a more general density-velocity relation \rho / \sigma _ { D } ^ { \epsilon } . Conversely , when we enforce \rho / \sigma ^ { 3 } _ { r } \propto r ^ { - \eta } as an input , none of the physically allowed \rho ( occurring for the narrow range 1.8 \la \eta \leq 1.9444 ) follows the Einasto form . We expect the next-generation simulations with better spatial resolution to settle the debate : either the Einasto profile will continue to hold and \rho / \sigma ^ { 3 } _ { r } will deviate from a power law , or \rho / \sigma ^ { 3 } _ { r } will continue as a power law and \rho will deviate from its current parameterizations .