  We study the renormalization of non-semisimple gauge models quantized in the
`t Hooft-background gauge to all orders. We analyze the normalization
conditions for masses and couplings compatible with the Slavnov-Taylor and
Ward-Takahashi Identities and with the IR constraints. We take into account
both the problem of renormalization of CKM matrix elements and the problem of
CP violation and we show that the Background Field Method (BFM) provides proper
normalization conditions for fermion, scalar and gauge field mixings. We
discuss the hard and the soft anomalies of the Slavnov-Taylor Identities and
the conditions under which they are absent.
