  Recently, a geometric model for the confinement of magnetic charges in the
context of type II string compactifications was constructed by Greene, Morrison
and Vafa. This model assumes the existence of stable magnetic vortices with
quantized flux in the low energy theory. However, quantization of flux alone
does not imply that the vortex is stable, since the flux may not be confined to
a tube of definite size. We show that in the field theoretical model which
underlies the geometric model of confinement, static, cylindrically symmetric
magnetic vortices do not exist. While our results do not preclude the existence
of confinement in a different low-energy regime of string theory, they show
that confinement is not a universal outcome of the string picture, and its
origin in the low energy theory remains to be understood.
