  We briefly review the cases of forced and spontaneous chiral symmetry
breaking. In particular the chiral condensate of q anti-q pairs is parametrized
with two angles, phi which measures the chiral condensation, and theta which
measures the chiral rotation. The strong CP problem arises when it is assumed
that the current quark masses of the Standard Model, have a theta phase that
differs from the phase induced by the instanton term wich is originated in the
QCD sector of the Standard Model. We show how chiral symmetry breaking may
solve the strong CP problem at the BCS level. We show variationally that the
physical vacuum is CP conserving and therefore the interplay of the instanton
and the current mass terms cannot produce any strong CP violation. We also
study the possible effect of theta in weak interactions, and conclude that it
does not produce weak CP.
