[en] The path-integral formulation of Reggeon field theory at zero transverse dimension, D = 0, is examined. We point out the necessity of breaking the classical permutation symmetry and argue that this is accomplished by enforcing quantum stability conditions in a nonperturbative path-integral formalism. By breaking the permutation symmetry, we show that the tunneling effect for the D = 0 theory when the bare Pomeron intercept is greater than one is not due to classical instanton configurations; instead, tunneling comes about by a certain mixture of quantum and classical configurations. Our picture naturally leads to the ''instanton vacuum'' solution for the D not = 0 supercritical region advocated by White