It has been demonstrated that mathematically consistent Yang-Mills gau
ge theories can be constructed on the basis of a class of general Lie
algebras called quasiclassical, which contains reductive as well as a
class of solvable Lie algebras. However, if we require that these theo
ries should be ghost-free, then only the standard gauge theories based
upon compact Lie algebras are allowed. Nevertheless, these solvable g
auge theories may be relevant for some integrable models based upon th
e zero-curvature condition.