  It is expected that, within the next three years, the determination of the
CKM matrix elements with the least theoretical uncertainty will arise from the
measurements of CP violation in B_d --> J/\psi K_S decays and from Bs-Bsbar
mixing. If there is significant new physics in Bs-Bsbar mixing, then those
experiments will not yield the correct values for the CKM matrix elements. As a
result, a qualitative signal of new physics may appear in the CP violation of
decays like B_d --> pi+ pi-.
