  We investigate the dynamics of monopole annihilation by the Langacker-Pi
mechanism. We find taht considerations of causality, flux-tube energetics and
the friction from Aharonov-Bohm scatteering suggest that the monopole
annihilation is most efficient if electromagnetism is spontaneously broken at
the lowest temperature ($T_{em} \approx 10^6 GeV$) consistent with not having
the monopoles dominate the energy density of the universe.
