  In this paper we consider the two-loop calculation of the disjoining pressure
of a symmetric electrolytic soap film. We show that the disjoining pressure is
finite when the loop expansion is resummed using a cumulant expansion and
requires no short distance cut-off. The loop expansion is resummed in terms of
an expansion in g=l_B/l_D where l_D is the Debye length and l_B is the Bjerrum
length. We show that there there is a non-analytic contribution of order
g*ln(g). We also show that the two-loop correction is greater than the one-loop
term at large film thicknesses suggesting a non-perturbative correction to the
one-loop result in this limit.
