National Security Is a Good Reason for Protection. But Not of Steel and Aluminum

The biggest problem with President Trump’s steel and aluminum tariffs isn’t what they’ll do to the price of a can of beer, which is made from aluminum, or a gallon of gasoline, which is extracted, refined, and delivered by an infrastructure of steel. Nor is it the risk of retaliation by China, which has launched a probe into imports of sorghum from the U.S. and is studying whether to cut back on American soybeans.

The biggest problem is the precedent the tariffs set. The U.S. is invoking national security to bust out of the delicate web of trade agreements that it’s spent decades carefully spinning. The World Trade Organization is far from perfect, but if countries begin to ignore it and start slapping high tariffs and quotas on one another, global trade growth could shudder to a halt. That would harm everyone.