In particular, the "serious prejudice" claim of the Agreement on Subsidies and Countervailing Measures (SCM), Article 5(c), according to expert opinion, is a lower threshold for achieving successful challenges than the injury requirement under a countervailing duty claim. If challenges are successful, the WTO remedy likely would imply either elimination, alteration, or amendment by Congress of the programs in question to remove their adverse effects. Alternately, in light of an adverse ruling the United States could choose to make compensatory payments (under agreement with the challenging country) to offset the alleged injury. To identify commodities that are potentially vulnerable to WTO challenges, USDA data are used to measure the level of subsidy dependence. Do U.S. Farm Subsidies Cause Adverse Effects in the Marketplace? (The longer version of this report, CRS Report RL33697, Potential Challenges to U.S. Farm Subsidies in the WTO , by [author name scrubbed], summarizes these studies.) Conclusions

When measured against WTO criteria, all major U.S. subsidized crops (both "covered commodities" and "loan commodities") appear potentially vulnerable to WTO legal challenges. As a result, U.S. subsidy programs would appear vulnerable to WTO challenge under SCM Article 5 and 6.3 following even such a policy reform.
This report examines U.S. commodity subsidy programs against an emerging set of criteria that test their potential vulnerability to challenge in the World Trade Organization. The criteria are whether the subsidies cause adverse effects contributing to serious prejudice under the Agreement on Subsidies and Countervailing Measures (SCM), Articles 5 and 6.3. When measured against these criteria, available evidence suggests that all major U.S. subsidy program crops, particularly crops receiving benefits under both the counter-cyclical payments program and marketing loan provisions are potentially vulnerable to dispute settlement challenges. If such challenges occur and are successful, the WTO remedy likely would imply either elimination, alteration, or amendment by Congress of the programs in question to remove their adverse effects. Alternately, in light of an adverse ruling the United States could choose to make compensatory payments (under agreement with the challenging country) to offset the alleged injury. In spite of U.S. vulnerability, there are reasons why challenges may rarely be filed. Disputes are economically and diplomatically costly, and a lost challenge can help to legitimize the disputed program. This report, which will be updated, is an abridged version of CRS Report RL33697, Potential Challenges to U.S. Farm Subsidies in the WTO , by [author name scrubbed]. Citations to sources appear in that report.