Abstract
We derive the two-loop evolution equations for the Cabibbo-Kobayashi-Maskawa matrix. We show that to leading order in the mass and CKM hierarchies the scaling of the mixings \(|V_{ub}|^2\), \(|V_{cb}|^2\), \(|V_{td}|^2\), \(|V_{ts}|^2\) and of the rephase-invariant CP-violating parameter \(J\) is universal to all orders in perturbation theory. In leading order the other CKM elements do not scale. Imposing the constraint \(\lambda _b=\lambda _{\tau}\) at the GUT scale determines the CKM scaling factor to be \(\simeq 0.58\) in the MSSM.