Say there's an anthrax attack in a major U.S. city, and you want to get antibiotics to everybody in town. It's a problem federal health officials have been trying to crack for years, and they think they've found an answer: The U.S. Postal Service.

"We have found letter carriers to be the federal government's quickest and surest way of getting pills to whole communities," the blogger Mike Leavitt, who also runs the Department of Health and Human Services, tells the Washington Post.

In...