How General Is the Case for Unilateral Tariff Reduction
反驳了单边关税削减必然优于关税同盟的观点，通过一个例子说明关税同盟可能更优，并指出支持单边削减的假设条件过于狭窄，不具普遍性。
In this Review (1981), we attacked a proposition (P1) of Eitan Berglas (1979) and others, that unilateral tariff reduction (UTR) is necessarily superior to customs union (CU), provided scale economies and changes in terms of trade are ruled out. We put forward a much weaker proposition (P2) (p. 706) that UTR is sometimes superior, sometimes inferior. In his 1983 paper, (p. 1142), Berglas concedes that our 1981 Figure 2 (which he calls example El) illustrates CU superiority. He thereby concedes our main point: P2 is correct; P1 is not. A question remains: how interesting is the domain where UTR is superior?' We argued (1981) UTR is superior under narrow assumption Al (partner B's tariffs can be ignored) or A2 (no tariff by outsider C nor transport costs in trade with C). But a CU is superior in our main example (Figure 2), where neither Al nor A2 holds, and partners A and B trade with mutual benefit in the price wedge between C's import and export prices. In addition to wrongly claiming we were illogical and incorrect,2 Berglas argues (1983) that there are two other assumptions in his 1979 paper which, taken together, are also sufficient to establish UTR superiority. However, he misstates them. They are not, as he says, A3 (the CU does not affect the direction of trade) plus A4 (all three countries trade). Instead, they are A3 plus a much more restrictive A5: C trades every good with the CU. (This assumption, in Berglas, 1979, Figure 1 and Table 1, is distinguishable from A4 only when there are more than two goods.) Why must A5 be assumed, not just A4? Without A5, trade between A and B can occur in some goods within C's price wedge. In short, Berglas establishes UTR superiority by A5, assuming that A and B can't trade in the wedge where CU provides mutual benefits. (Our wedge becomes increasingly important in the n-good case. Consider cement, for example.) Moreover, Berglas's A3 rules out changes in trade patterns, and therefore Viner's concepts of trade diversion and trade creation which introduced the modern CU debate. Like a case based on Al or A2, the A3 + A5 case for UTR superiority is not interesting. Even if it were, one more special case does not establish the general principle that UTR is necessarily superior to a CU, any more than one more example where protection raises welfare would establish a general proposition that protection necessarily raises welfare.