  We study a typical complete gluonic phase (LGP) in two-flavor color
superconductivity (2SC) by calculating the essential cubic and quartic
interfering term between the gluonic condensates $<A^{(8)}_{z}>$ and
$<A^{(6)}_{z}>$ with a gauged NJL model. It is proven that the coefficient of
the cubic interfering term and the vacuum contributions of the cubic and
quartic interfering term are all equal to zeroes. The coefficients of the
quartic interfering term and the $<A^{(6)}_{z}>$'s quartic self-interaction
term at stationary points of LOFF phase are calculated. Comparisons among the
effective potentials of LGP, g2SC and LOFF phase indicate that LGP could be the
genuine ground state of 2SC for some reasonable parameters.
