  We analyze electron transport through relatively short coherent conductors in
the presence of Coulomb interaction. We evaluate the current-voltage
characteristics of such conductors taking into account the effect of an
external environment. Within our model, at large conductances and low $T$ the
conductance is suppressed by a universal factor which depends only on the type
of the conductor. We also argue that at T=0 the system ``scatterer+shunt'' can
be either an insulator or a metal depending on whether its total resistance is
larger or smaller than $R_Q=h/e^2\approx 25.8$ k$\Omega$. In a metallic phase
the Coulomb gap is fully suppressed by quantum fluctuations.
