  The 2.6 sigma deviation in the muon's anomalous magnetic moment has strong
implications for supersymmetry. In the most model-independent analysis to date,
we consider gaugino masses with arbitrary magnitude and phase, and sleptons
with arbitrary masses and left-right mixings. For tan(beta)=50, we find that 1
sigma agreement requires at least one charged superpartner with mass below 570
GeV; at 2 sigma, this upper bound shifts to 850 GeV. The deviation is
remarkably consistent with all constraints from colliders, dark matter, and b
-> s gamma in supergravity models, but disfavors the characteristic gaugino
mass relations of anomaly-mediation.
