Implications of the possibility thatsin2βis small

Recently, the Babar and Belle Collaborations have reported their first measurements of the $\mathrm{CP}$-violating asymmetry in $B_d\to \psi K_S,$ and more precise results will follow soon. We discuss what future evidence for small $\sin 2\beta$ could mean, contrasting the usual possibility of new physics in the $B_d$ system with the interesting alternative that the new physics effects are confined to the kaon system.