  It has been shown that by using a Lagrange multiplier field to ensure that
the classical equations of motion are satisfied, radiative effects beyond
one-loop order are eliminated. It has also been shown that through the
contribution of some additional ghost fields, the effective action becomes form
invariant under a redefinition of field variables, and furthermore, the usual
one-loop results coincide with the quantum corrections obtained from this
effective action. In this paper, we consider the consequences of a gauge
invariance being present in the classical action. The resulting gauge
transformations for the Lagrange multiplier field as well as for the additional
ghost fields are found. These gauge transformations result in a set of
Faddeev-Popov ghost fields arising in the effective action. If the gauge
algebra is closed, we find the Becci-Rouet-Stora-Tyutin (BRST) transformations
that leave the effective action invariant.
