  A detailed analysis of the spherically symmetric isolated horizon system is
performed in terms of the connection formulation of general relativity. The
system is shown to admit a manifestly SU(2) invariant formulation where the
(effective) horizon degrees of freedom are described by an SU(2) Chern-Simons
theory. This leads to a more transparent description of the quantum theory in
the context of loop quantum gravity and modifications of the form of the
horizon entropy.
