  It may be possible to approximate the full pion wave function in light-front
QCD using only $q \qbar$ and $q \qbar g$ Fock space components. Removing zero
modes and using invariant-mass cutoffs that make a constituent approximation
possible leads to non-canonical terms in the QCD hamiltonian, and forces us to
work in the broken symmetry phase of QCD in which chiral symmetry breaking
operators must appear directly in the hamiltonian because the vacuum is
trivial. Assuming any candidate interactions are local in the transverse
direction, I argue that they are probably relevant operators so that
perturbation theory is not modified at high energies. Since light-front chiral
symmetry corresponds to quark helicity conservation, we can readily identify
candidate chiral symmetry breaking interactions. The only candidate relevant
operator is the quark-gluon emission/absorption operator with a quark spin
flip. I argue that this operator can only produce the physical $\pi-\rho$ mass
splitting if the $q \qbar g$ component of the pion is significant.
