  I show that a standard application of the semiclassical techniques to 1+1
dimensional field theories, as originally discussed by Dashen, Hasslacher and
Neveu, explicitly violates the Poincare algebra. This problem is traced to the
incorrect regularization of the ultraviolet divergences and can be resolved by
using a different regularization. I further show that in the case of the
doublet solutions in the sine-Gordon theory the semiclassical treatment given
by Dashen, Hasslacher and Neveu leads to ambiguous results which depend on the
choice of the renormalization counterterm. I discuss a consistent weak coupling
expansion which does not suffer from this problem.
