The EU has warned the US that it could be in violation of world trade rules if they do not allow Cash for Clunker trade-ins for non-US cars:

The United States would violate world trade rules if proposed government payments to encourage consumers to trade in old gas-guzzling cars can be used to buy only new American-made vehicles, a European Union official said Wednesday.

“It is our hope that any car scrappage legislation ultimately enacted will remedy these concerns, and that the EU will be able to support this important initiative to promote fuel-efficiency, reduce pollution, and provide a needed boost to the automobile industry,” John Bruton, the EU’s ambassador to the United States, said in a statement.