  The dependence of elliptic flow at RHIC energies on the effective parton
scattering cross section is calculated using the ZPC parton cascade model. We
show that the v_2 measure of elliptic flow saturates early in the evolution
before the hadronization transition to a rather large value ~0.05-0.15 as
\sigma_g varies from 2-10 mb and thus is a sensitive probe of the dynamics in
the plasma phase.
