perturbative framework, supports more precise predictions for high-energy experiments. Also, if we are to have confidence in using lattice QCD as a mathematical tool for determining weak matrix elements, we need to make sure it gives consistent, accurate results for a variety of quantities in spectroscopy and electromagnetic transitions, where the underlying physics is securely known. These quantities, of course, are just those that go into the lattice QCD determination of $\alpha_s$.

Precision determination of $\alpha_s$ will also add to the power of the unification of couplings calculation, which at present provides our best quantitative handle on fundamental physics beyond the standard model. The central value is on the low side for supersymmetric grand unified theories, but perhaps within the margin of plausible threshold corrections. If and when we start to pin down the low-energy supersymmetric spectrum, we will be able to leverage this precision to gain insight into how unification symmetry and supersymmetry are broken.

Finally, I think it’s very legitimate to regard precise determination of $\alpha_s$ as an end in itself. Together with the electron mass, the ordinary fine structure constant $\alpha$, and the up and down quark masses, $\alpha_s$ is one of a handful of parameters that 