  We present a gauge independent method to construct the effective action of
QCD, and calculate the one loop effective action of $SU(2)$ QCD in an arbitrary
constant background field. Our result establishes the existence of a dynamical
symmetry breaking by demonstrating that the effective potential develops a
unique and stable vacuum made of the monopole condensation in one loop
approximation. This provides a strong evidence for the magnetic confinement of
color through the dual Meissner effect in the non-Abelian gauge theory. The
result is obtained by separating the topological degrees which describe the
non-Abelian monopoles from the dynamical degrees of the gauge potential, and
integrating out all the dynamical degrees of QCD. We present three independent
arguments to support our result.
