  I examine various ideas for radiative polarization at TLEP/FCC-ee and
formulate some estimates for the polarization buildup time and the asymptotic
polarization. Using wigglers, a useful degree of polarization (for energy
calibration), with a time constant of about 1 h, may be possible up to the
threshold of $W$ pair production. At higher energies such as the threshold of
Higgs production, attaining a useful level of polarization may be difficult in
a planar ring. With Siberian Snakes, wigglers and some imagination,
polarization of reasonable magnitude, with a reasonable time constant (of not
more than about 1 h), may be achievable at very high energies.
