  Stirling et al. (2003) reported the discovery of a 2.3 year periodic
variation in the structural position angle of the parsec-scale radio core of
the blazar BL Lac. We searched for independent confirmation of this periodic
behavior using 43 GHz images of the radio core during ten epochs overlapping
those of Stirling et al. Our maps are consistent with several periodicities,
including one near the period reported by Stirling et al. By comparing our
position angle measurements with those of Stirling et al., we find strong
consistent evidence for position angle variations of the inner core during the
observed epochs. However, the claim for periodic variation is not convincing,
especially when the most recent epochs (2000.60 - 2003.78) are included. A
definitive resolution will require continued monitoring of the core structure
over several periods.
