  In the large $N_c$ approximation to $QCD$, the leading $\pp$ scattering
amplitude is expressed as the sum of an infinite number of tree diagrams. We
investigate the possibility that an adequate approximation at energies up to
somewhat more than one $GeV$ can be made by keeping diagrams which involve the
exchange of resonances in this energy range in addition to the simplest chiral
contact terms. In this approach crossing symmetry is automatic but individual
terms tend to drastically violate partial wave unitarity. We first note that
the introduction of the $\rho$ meson in a chirally invariant manner
substantially delays the onset of drastic unitarity violation which would be
present for the {\it current algebra} term alone. This suggests a possibility
of local (in energy) cancellation which we then explore in a phenomenological
way. We include exchanges of leading resonances up to the $1.3 GeV$ region.
However, unitarity requires more structure which we model by a four derivative
contact term or by a low lying scalar resonance which is presumably subleading
in the $\1N$ expansion, but may nevertheless be important. The latter two
flavor model gives a reasonable description of the phase shift $\delta^0_0$ up
until around $860 MeV$, before the effects associated which the $K\bar{K}$
threshold come into play.
