  The application of the background-field method to the electroweak Standard
Model and its virtues are reviewed. Special emphasis is directed to the Ward
identities that follow from the gauge invariance of the background-field
effective action. They are compatible with on-shell renormalization and imply a
decent behavior of the background-field vertex functions. Via the usual
construction of connected Green functions they transfer to Ward identities for
connected Green functions which, in distinction to the conventional formalism,
remain exactly valid in finite orders of perturbation theory even if a Dyson
summation of self-energies (within a systematic use of one-particle irreducible
building blocks) is performed. Finally, we comment on the interplay between
gauge invariance and gauge-parameter (in-)dependence of vertex and Green
functions and the uniqueness of resummation procedures.
