  We provide two independent systematic methods of performing $D$-dimensional
physical-state sums in gauge theory and gravity in such a way so that spurious
light-cone singularities are not introduced. A natural application is to
generalized unitarity in the context of dimensional regularization or theories
in higher spacetime dimensions. Other applications include squaring matrix
elements to obtain cross sections, and decompositions in terms of
gauge-invariant tensors.
