We construct a three-country, two-bloc, multi-product trade model in which
tariff agreements between customs union members are binding whereas inter-b
loc tariff agreements are self-enforcing. Our main objective is to explore
how the liberalization of trade between customs union members (i.e. the dee
pening of regional integration) affects the sustainability of tariff agreem
ents with the rest of the world (ROW). We derive conditions under which Kem
p-Wan [Kemp, M.C. and ii. Wan, Jr., 1976, An elementary proposition concern
ing the formation of customs unions, Journal of International Economics 6,
95-97] adjustments in the external tariffs of union members result in self-
enforcing tariff agreements with ROW and then use these adjustments to eval
uate the general tariff-setting incentives of the two trading blocs. (C) 20
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