  The problem of defining a gauge invariant effective potential with a strict
energetic interpretation is examined in the context of spontaneously broken
gauge theories. It is shown that such a potential can be defined in terms of a
composite gauge invariant order parameter in physical gauges. This effective
potential is computed through one loop order in a model with scalars and
fermions coupled to an abelian gauge theory, which serves as a simple model of
the situation in electroweak theory, where vacuum stability arguments based on
the scalar effective potential have been used to place lower bounds on the
Higgs mass.
