  We revisit and clarify some aspects of perturbative renormalization in pure
Chern-Simons theory by means of a localization principle associated with an
underlying supersymmetry. This perspective allows the otherwise perturbative
one-loop shifts to be interpreted as nonperturbative consequences of a
non-renormalization theorem, while providing a unified understanding of their
origin (particularly in the case of Wilson lines). We illustrate this approach
explicitly for $SU(2)$ Chern-Simons theory in flat space, on Seifert manifolds,
and on a solid torus.
