The time integrated CP asymmetry in the decay of a neutral B meson to a CP eigenstate has been claimed to be free of uncertainties arising from hadronic matrix elements (modulo the mixing parameter Δ m Λ ). That is, it is a direct measure of KM angles. We scrutinize this claim, and question its generality. To this end we compute the effective hamiltonian for ΔB=1, charm and up conserving processes, in the leading logarithmic approximation. Enhancement of hadronic matrix elements of “penguin” operators could easily invalidate the claim.