The U.S. has been doing pretty well in the WTO's dispute resolution system (measuring success by simple win-loss counts).
The U.S. Trade Representative maintains a more or less up-to-date scorecard: Snapshot of WTO Cases Involving the United States (update July 31, 2007).
Here's a pie-chart summarizing the USTR's score-keeping. The chart shows cases in which decisions have been reached, or the parties have come to an agreement that short-circuited the ongoing settlement process (resolved). There are many cases still in the pipeline. Blue cases were resolved through negotiation, green cases were won by the U.S. on USTR-identified core issues, and red cases are those the U.S. lost.
On balance, the U.S. seems to be doing fairly well. In the overwhelming number of cases in which we are complaining we have won on the core issues, or have obtained a resolution through negotiation. We're not doing so well when we're the defendent. We've lost about half on the core issues, and won or negotiated solutions to about half. This is a crude measure of success and failure; it doesn't address the relative importance of the different cases, or the nature of the negotiated solutions.
On the other hand, Brandon Wu, at Public Citizen's "Eyes on Trade," thinks the U.S. is a big loser in WTO dispute settlement outcomes: We are the "world's biggest loser" (August 27):