  We discuss a consistent theory for a self-interacting vector field, breaking
an Abelian symmetry in such a way to obtain an interesting behavior for its
longitudinal polarization. In an appropriate decoupling limit, the dynamics of
the longitudinal mode is controlled by Galileon interactions. The full theory
away from the decoupling limit does not propagate ghost modes, and can be
investigated in regimes where non-linearities become important. When coupled to
gravity, this theory provides a candidate for dark energy, since it admits de
Sitter cosmological solutions characterized by a technically natural value for
the Hubble parameter. We also consider the homogeneous evolution when, besides
the vector, additional matter in the form of perfect fluids is included. We
find that the vector can have an important role in characterizing the universe
expansion.
