  We consider the color gauge invariance of a factorized description of the
Drell-Yan process cross section. In particular, we focus on the next-to-leading
twist contributions for polarized scattering and on the cross section
differential in the transverse momentum of the lepton pair in the region where
the transverse momentum is small compared to the hard scale. The hadron tensor
is expressed in terms of manifestly color gauge invariant, nonlocal operator
matrix elements and a color gauge invariant treatment of soft gluon poles is
given. Also, we clarify the discrepancy between two published results for a
single spin asymmetry in the Drell-Yan cross section. This asymmetry arises if
such a soft gluon pole is present in a specific twist-three hadronic matrix
element.
