with commitments under a trade agreement are related to local prices in the domestic economy, and any set of local prices that can be achieved via preferential tari¤ cuts can be achieved as well with appropriate MFN tari¤s.

Finally, we turn to the third question: Is there evidence that commitment motives are important for understanding real-world trade agreements? Here the evidence is thin but supportive. Staiger and Tabellini (1999) o¤er early empirical support for the commitment theory. They look for evidence that governments make di¤erent tari¤ choices across GATT environments that are distinguished by the degree of commitment that GATT rules provide for those choices. Focusing on US tari¤ choices made under the GATT Escape Clause (where GATT should not have helped provide commitment) and made in the Tokyo Round of GATT negotiations (where GATT rules could have helped provide commitment), Staiger and Tabellini ...nd that US tari¤ decisions were more responsive to the production distorting impacts of the tari¤s in the latter decisions as compared to the former decisions, in line with what their commitment model would predict. Tang and Wei (2009) adopt a di¤erent approach. They consider the di¤erences in the growth performance of developing countries that joined the GATT/WTO under two di¤erent kinds of accession rules, rules that applied in GATT prior to the creation of the WTO and that did not require acceding countries to undertake extensive policy commitments, and rules that applied subsequent to the creation of the WTO in 1995 and that typically required substantial policy commitments by the acceding government. Tang and Wei ...nd that the post-accession growth performance of the developing countries that acceded to the GATT/WTO under the latter set of rules was signi...cantly better than that of non-acceding countries and countries that acceded to GATT under the former rules, and they attribute this di¤erence to the domestic commitment role played by the WTO. Further evidence lending some support to the commitment theory of trade agreements is provided by Limão and Tovar (2011), Liu and Ornelas (2014) and Bown and Crowley (2014).<sup>124</sup> Summarizing, we conclude from our survey of the commitment theory strand of the literature that this theory provides some reason to be more supportive of PTAs than our survey of the termsof-trade theory alone would suggest, though it provides no reason to be less supportive of the WTO. We thus see the commitment theory as moving the answer to the motivating question of our survey toward a view that PTAs and the WTO may be complementary, but in light of the relatively thin empirical support to date on the widespread importance of the commitment theory’s role in actual trade agreements, probably not as yet moving the answer very far in this direction.

> resources would be una¤ected as well).

> 124 Limão and Tovar (2011) (see note 118) employ data on Turkish tari¤s and non-tari¤ barriers and ...nd evidence in line with their theory that Turkey was more likely to bind its tari¤s in the WTO and to bind them more tightly in industries where it had low bargaining power relative to the lobbies it faced. Liu and Ornelas (2014) (see note 120) ...nd evidence supporting the two key predictions of their model that PTAs are more likely to be formed by unstable democracies and participation in PTAs helps to stabilize these democracies. Finally, in their cross-country study of emerging economies, Bown and Crowley (2014) provide evidence that these countries changed how they conduct their trade policy (through antidumping and safeguards) by taking on tari¤ binding commitments when joining the WTO.

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