If the feds really want to help the economy post-Katrina, here are four words: lumber, cement, shrimp and steel. They all have prices higher than necessary because of U.S. anti-dumping trade law. Start with lumber and cement, which will soon be in great demand to rebuild the tens of thousands of damaged homes. Prices are sure to rise as reconstruction begins, but thanks to U.S. tariffs as high as 27% on Canadian lumber, American home buyers already pay an extra $1,000 on average for their shelter. The same goes for U.S. duties on Mexican cement, which have averaged 55% since...