  We define a CP-asymmetric observable that is sensitive to CP-violating
interactions in the gauge-boson sector. We illustrate the utility of this
observable by studying how well the LHC can measure the coefficient of a
particular dimension-six WWZ operator. We find that sensitivity at the 10^{-3}
level is possible at the LHC with 100 fb^{-1} of integrated luminosity, which
would greatly exceed the sensitivity achieved at LEP, and would rival or may
even better the indirect sensitivities inferred from related operators
constrained by electric dipole moment experiments.
