In this paper we develop some simple models of optimal tax and tariff
policy in the presence of global corporations that operate in an imper
fectly competitive environment. The models emphasize two important dif
ferences in the practical application of tax and tariff policy - tax,
but not tariff, policy can apply to offshore output, and tariff, but n
ot tax, policy can be industry-specific. Recognizing that multinationa
ls' production decisions are endogenous to the tax and tariff policies
they face, we investigate how a government should tax (or subsidize)
domestically owned firms and how government should set trade policy.