  Under a rescaling of longitudinal coordinates $x^{0,3}$ by a factor $\lambda$
which is taken to zero, the classical QCD action simplifies dramatically. This
is the high-energy limit, as $\lambda$ is of order $s^{-1/2}$, where $s$ is the
center-of-mass energy squared of a hadronic collision. We find the quantum
corrections to the rescaled action at one loop, in particular finding the
anomalous powers of $\lambda$ in this action, for $\lambda$ close to unity. The
method is an integration over high-momentum components of the gauge field. This
is a Wilsonian renormalization procedure, and counterterms are needed to make
the sharp-momentum cut-off gauge invariant. Our result for the quantum action
is found, assuming that the logarithm of $\lambda$ is small, which is essential
for the validity of perturbation theory. If $\lambda$ is sufficiently small (so
that its logarithm is large), then the perturbative renormalization group
breaks down. This is due to uncontrollable fluctuations of the longitudinal
chromomagnetic field.
