  We study the issue of symmetries and associated Ward-like identities in the
context of two-particle-irreducible (2PI) functional techniques for abelian
gauge theories. In the 2PI framework, the $n$-point proper vertices of the
theory can be obtained in various different ways which, although equivalent in
the exact theory, differ in general at finite approximation order. We derive
generalized (2PI) Ward identities for these various $n$-point functions and
show that such identities are exactly satisfied at any approximation order in
2PI QED. In particular, we show that 2PI-resummed vertex functions, i.e.
field-derivatives of the so-called 2PI-resummed effective action, exactly
satisfy standard Ward identities. We identify another set of $n$-point
functions in the 2PI framework which exactly satisfy the standard Ward
identities at any approximation order. These are obtained as field-derivatives
of the two-point function $\bcG^{-1}[\phi]$, which defines the extremum of the
2PI effective action. We point out that the latter is not constrained by the
underlying symmetry. As a consequence, the well-known fact that the
corresponding gauge-field polarization tensor is not transverse in momentum
space for generic approximations does not constitute a violation of (2PI) Ward
identities. More generally, our analysis demonstrates that approximation
schemes based on 2PI functional techniques respect all the Ward identities
associated with the underlying abelian gauge symmetry. Our results apply to
arbitrary linearly realized global symmetries as well.
