  We study the low temperature phase of the 3D Coulomb glass within a mean
field approach which reduces the full problem to an effective single site model
with a non-trivial replica structure. We predict a finite glass transition
temperature $T_c$, and a glassy low temperature phase characterized by
permanent criticality. The latter is shown to assure the saturation of the
Efros-Shklovskii Coulomb gap in the density of states. We find this pseudogap
to be universal due to a fixed point in Parisi's flow equations. The latter is
given a physical interpretation in terms of a dynamical self-similarity of the
system in the long time limit, shedding new light on the concept of effective
temperature. From the low temperature solution we infer properties of the
hierarchical energy landscape, which we use to make predictions about the
master function governing the aging in relaxation experiments.
