the site.<sup>18</sup> There is considerable time-series variation as well as cross-sectional variation in the data.

Lobbying data were constructed as described in Section 3 from FEC databases for each election cycle between 1991 and 2000.<sup>19</sup> Goods are ordered by the of PAC spending-toproduction ratio.<sup>20</sup> Agricultural protection is primarily measured as nontariff measure coverage ratios, or NTMs.<sup>21</sup> Data on the incidence of nontariff measures are from the UNCTAD TRAINS database for the years 1993, 1996, and 1999.<sup>22</sup> There are over 150 types of NTMs documented by UNCTAD, and the measure used here is simply the coverage ratio of the union of all NTMs. This measure, though it aggregates price-type, quantity-type, and investigations-type of NTMs, each with different price-effects, has nevertheless been used in prominent studies of the political economy of trade protection (Trefler, 1993; Gawande and Bandyopadhyay 2000; Goldberg and Maggi, 1999). The TRAINS database also allow narrower NTM classifications such as Price NTMs (P) and threat NTMs (THR), 18 The USDA system is not originally kept at the HS level. The coding into HS was done manually from verbal description. They fit HS 4- or 5-digits descriptions almost perfectly.

19 Numerous checks have been applied to the lobbying data constructed for this paper. For example, the data are in close proximity to the numbers reported in Opensecrets (2002). A detailed data appendix that describes steps in the construction of the PAC data is available from the author.

20 Production value is not immediately available, since the PSD database keeps data in quantities, not values, and units of measurement are disparate across goods. But imports can be recovered by dividing the import-to-output ratio by imports (from UNCTAD, see below) in order to recover value of production. Where imports are zero this method does not allow measurement of production, and those observations have to be dropped. Fortunately, imports are strictly zero for only few goods.

21 Agricultural protection may be measured using ad valorem tariffs as well. Model (3) was also estimated using four tariffs measures are available. Three measures are from the UNCTAD TRAINS database at the 6-digit HS levels for 1993, 1996, and 1999. They are an ad valorem measure, a specific tariff measure, and a tariff coverage measure. The fourth measure is an ad valorem tariff measure from the International Trade Commission (ITC) database at the 8-digit HS level for 19972001. Import-weighted averages of these tariffs were used to concord to the 4- and 5-digit HS level of the PSD goods at which the analysis is conducted. While specific tariffs are well explained by the model and reported in the tables, the ad valorem tariff data are not well explained by the variables included. This is probably because tariffs have been determined multilaterally and are not appropriate for testing models of unilateral protection. The tariff results are available from the author.

22 From the raw data on the UNCTAD TRAINS database, Haveman has constructed binary indicators of NTMs at the 6 digit HS level. These are used in the present analysis. The TRAINS database does have some unresolved issues, some of which are corrected in more recent versions, but recent versions have only recent-dated NTM data.

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