  We give a new interpretation of the chromatic polynomial of a simple graph G
in terms of the Kac-Moody Lie algebra with Dynkin diagram G. We show that the
chromatic polynomial is essentially the q-Kostant partition function of this
Lie algebra evaluated on the sum of the simple roots. Applying the Peterson
recurrence formula for root multiplicities, we obtain a new realization of the
chromatic polynomial as a weighted sum of paths in the bond lattice of G.
