  The appropriate power counting for the effective field theory of NN
interactions is reviewed. It is more subtle than in most effective field
theories since in the limit that the S-wave NN scattering lengths go to
infinity it is governed by a nontrivial fixed point. The leading two body terms
in the effective field theory for nucleon self interactions are scale invariant
and invariant under Wigner SU(4) spin-isospin symmetry in this limit. Higher
body terms with no derivatives (i.e., three and four body terms) are
automatically invariant under Wigner symmetry.
