  We generalize the discussion of hep-th/0509170 to charged black holes. For
the two dimensional charged black hole, which is described by an exactly
solvable worldsheet theory, a transition from the black hole to the string
phase occurs when the Hawking temperature of the black hole reaches a limiting
value, the temperature of free strings with the same mass and charge. At this
point a tachyon winding around Euclidean time in the Euclidean black hole
geometry, which has a non-zero condensate, becomes massless at infinity, and
the horizon of the black hole is infinitely smeared. For Reissner-Nordstrom
black holes in d\ge 4 dimensions, the exact worldsheet CFT is not known, but we
propose that it has similar properties. We check that the leading order
solution is in good agreement with this proposal, and discuss the expected form
of \alpha' corrections.
