In this paper, we review the debate on "new regionalism," focusing on the tools used to evaluate regional trade agreements (RTAs). We find that much analysis uses tools from old trade theory in the Viner-Meade tradition, focusing on trade creation, trade diversion, and terms-of-trade effects. These tools are adequate for the analysis of the effects of removing commodity trade barriers ("shallow" integration), but the comfortable Viner-Meade framework misses many of the impacts associated with new regionalism, which typically involves "deep integration," often between developing and developed countries. A framework for analyzing new regionalism should include dynamic changes such as trade-productivity links and endogenous growth theory, international factor mobility, the role of imperfect competition, rent seeking behavior, and political-economy considerations such as potential conflicts between regionalism and multilateralism. Agriculture poses problems for new regionalism because of high tariffs, the use of domestic subsidies and entrenched special interest groups, but the role of trade liberalization on its productivity is often overlooked. For developing countries, a crucial issue is whether and how regionalism can be part of a successful development strategy. While "new trade theory" is concerned with a number of the issues relevant to new regionalism, and is providing new tools, the work is eclectic and is far from providing a unified framework for empirical analysis of new regionalism. Both theoretical and empirical research is needed to improve the reach and scope of new trade theory applied to issues of new regionalism.