  It is proven that, for any soft potential characterized by a finite Fourier
transform $\widetilde{\phi}(k)$, the virial and energy thermodynamic routes are
equivalent for approximations such that the Fourier transform of the total
correlation function divided by the density $\rho$ is an arbitrary function of
$\rho\beta\widetilde{\phi}(k)$, where $\beta$ is the inverse temperature. This
class includes the mean spherical approximation as a particular case.
