  We study the evolution of the power spectrum of gravitational potential
during the nonlinear clustering in an $\Omega=1$ matter dominated phase. N-body
simulations suggest that the potential does not evolve in time even in the
quasilinear phase for an $n=-1$ power spectrum. For $n=-2$, the potential
evolves in the quasilinear phase but not in the extreme nonlinear phase.
Becauase of these facts, the evolution of the gravitational potential in
spectra like CDM is less than what would have been expected naively. We discuss
a class of CDM like models in which such an interesting conspiracy between the
amplitude and local index occurs.
