World Trade Organisation rules against US dolphin safe labeling which has made significant reductions in the millions of dolphin deaths (another source says 97% reduction).
The US had already weakened the law in a series of amendments including replacing the import ban with a voluntary labeling policy, but ultimately lost and must now pay compensation to Mexican fishers or make further changes to the law.
Full story, external link WTO Ruling on Dolphin-Safe Tuna Labeling Illustrates Supremacy of Trade Agreements
In a similar way Canada and Mexico are attacking the US country of origin labeling (cool) for beef and pork which may see the World Trade Organisation rule it is a “barrier to trade”.
Update, Country of Origin labelling, 9th Dec 2015,
“The WTO authorized over $1 billion annually in trade sanctions against the United States unless and until the popular consumer policy is weakened or eliminated. ”
In the same article a history of US law changes reacting to Investor State Dispute Settlements (ISDS) via the WTO
“After previous WTO rulings, the United States has rolled back U.S. Clean Air Act regulations on gasoline cleanliness rules successfully challenged by Venezuela and Mexico and Endangered Species Act rules relating to shrimping techniques that kill sea turtles after a successful challenge by Malaysia and other nations. The U.S. also altered auto fuel efficiency (Corporate Average Fuel Economy) standards that were successfully challenged by the European Union.”