  We examine the effect of walking technicolor dynamics on the electroweak $S$
parameter and contrast it with the effect of QCD-like technicolor dynamics. Our
main tools are the operator product expansion for the high-momentum behavior of
the electroweak gauge boson vacuum polarizations and the analyticity of these
polarizations which relate their low and high momentum behaviors. We show that
whereas in large QCD-like technicolor models $S$ is large and positive, in
walking technicolor models a negative contribution is emphasized, related to
the large anomalous dimension of the technifermion condensate. Thus in walking
technicolor $S$ is determined by a large cancellation of two competing effects.
This may result in much smaller values of $S$ than in QCD-like technicolor,
although considerable uncertainties are involved. We conclude that it is
impossible to rule out walking technicolor based on the present experimental
limits on $S$ and the present theoretical technology.
