A full plate of issues for the new U.S. trade czar

The newly confirmed U.S. trade representative, Katherine Tai, is about as qualified as a person can be for the job. Which is a good thing, because she already faces a series of challenges.

They aren’t necessarily the trade issues that grab the biggest headlines, like tough new negotiations with major rivals. In fact, one of the most important tasks for Tai is simply enforcement of existing deals with close U.S. trading partners.

Well-thought-out, well-enforced trade deals benefit all Americans, ensuring lower prices for consumers, higher earnings for businesses, and protections for workers and...