  We consider a new perturbation scheme in nonabelian gauge theory. Pure
Yang-Mills theory in three dimensions is taken as a concrete example. The
zeroth-order in the perturbative expansion is given by BF theory coupled to a
St{\" u}ckelberg-like field. The effective coupling for the expansion can be
small in the infrared regime, which implies that nonperturbative treatment of
Yang-Mills theory may be partially reduced to that of BF theory.
