  We show stable ergodicity of a class of conservative diffeomorphisms which do
not have any hyperbolic invariant subbundle. Moreover the uniqueness of SRB
measures for non-conservative $C^1$ perturbations of such diffeomorphisms. This
class contains strictly non-partially hyperbolic robustly transitive
diffeomorphisms by Bonatti-Viana and so we answer their question about the
stable ergodicity of such systems.
