This paper proves that most previous studies to solve for the optimal tariff rate have committed various mathematical mistakes. When the mistakes are corrected, such studies actually derive zero tariff rate. This paper then shows that the so-called tariff-protected offer curve does not exist, as...

This paper unveils a serious mistake committed by Kemp (1967). His positive tariff is actually an export subsidy. The corrected Kemp model implies that the whole optimal tariff theory must have been working in the wrong direction

This paper unveils the tricks of how Kahn achieves his optimal tariff theory. When corrected, the optimal tariff turns out to be zero or negative.Apart from David Ricardo's comparative advantage, the most influential theory in the international trade study must be the optimal tariff theory (C....

This paper disproves the optimal tariff theory. Any tariff or subsidy changes only the relative price, not the offer curve. Its tariff-affected terms-of-trade is actually an export-subsidy policy. This paper confirms that free trade is indeed universally beneficial

This paper changes the current view of tariff. It advocates taxing the exporters, rather than the importers. The new theory is based on the symmetry theorem developed earlier by Lerner. Taxing the exporters has all the same effects as taxing the importers with tariff, except that the former...

This paper points out some mistakes in the so-called optimal tariff theory. When they are corrected, the trade model does not offer any welfare implication. It removes a major blocking stone for the World Trade Organization to promote free trade