  A purely left-chiral model of the weak interactions is used to show that the
total parity-violating asymmetry in quark-quark scattering must grow with
increasing energy. In the absence of other new physics, non-observation of a
large asymmetry can therefore be used to infer an upper bound on the mass scale
for new right-chiral weak vector bosons. Applying this idea to actual
nucleon-nucleon scattering requires more involved calculations, as the dominant
contribution appears to come from a component of diquark-quark scattering
related to, but not identical to, wavefunction-mixing. Earlier criticism of
this model by Simonius and Unger is refuted and a new calculation is proposed
as an additional check on the result. Finally, we argue that the so-called
`spin crisis' does not affect our conclusions. (Talk given at the BNL workshop
on future directions in particle and nuclear physics at multi-GeV hadron beam
facilities, March 4--6, 1993.)
