We discuss random matrix models for the spontaneous breaking of both chiral
and color symmetries at zero chemical potential and finite temperature.
Exploring different Lorentz and gauge symmetric color structures of the random
matrix interactions, we find that spontaneous chiral symmetry breaking is
always thermodynamically preferred over diquark condensation. Stable diquark
condensates appear only as SU(2) rotated chiral condensates, which do not
represent an independent thermodynamic phase. Our analysis is based on general
symmetry arguments and hence suggests that no stable and independent diquark
phase can form in QCD with two flavors at zero quark chemical potential.Comment: 26 pages, 1 figure, uses ReVTeX and epsf.st