  We argue that most of the relativistic 3-D (quasipotential) equations used in
hadron physics are inconsistent with the discrete symmetries like charge
conjugation and CPT, yielding an incorrect Lorentz structure for the calculated
Green's functions. An exception to this is the equal time approximation to the
Bethe-Salpeter equation. We present a covariant quasipotential model for the
pion-nucleon interaction based on hadronic degrees of freedom and satisfying
the full covariance.
