  Motivated by the recent controversy surrounding the Kerr effect measurements
in strontium ruthenate \cite{xia:167002}, we examine the electromagnetic
response of a clean chiral p-wave superconductor. When the contributions of the
collective modes are accounted for, the Hall response in a clean chiral
superconductor is smaller by several orders of magnitude than previous
theoretical predictions and is too small to explain the experiment. We also
uncover some unusual features of the collective modes of a chiral
superconductor, namely, that they are not purely longitudinal and couple to
external transverse fields.
