There have been exceptions. Some recent North-South PTAs have required the Southern partner to undertake significant reforms on a non-preferential basis. For example, the recent PTA between the United States and Chile requires Chile to make significant changes to its customs administration and product standards. But Chile is one country with a recent history of significant unilateral trade reforms, despite its offensive interests in the Doha Round (particularly in agriculture). Other countries that have made significant non-preferential concessions in a PTA context are some of the transition economies, which have yet to claim a stake in the WTO and its multilateral negotiations (this point is also made by Ethier, 1998a, 1998b, 1999 and 2001). But many of the East Asian economies have at least some offensive interests in the Doha Round, and are likely to be constrained in the offers they make in a PTA context accordingly.