WASHINGTON — A big part of Magistrate Judge Stephen W. Smith’s job in Federal District Court in Houston is to consider law enforcement requests for cellphone and e-mail records. It requires him to apply old laws to the digital age and balance the government’s interest in solving crimes against the importance of protecting privacy.

That is hard enough. What he has trouble understanding is why all this is kept from public view.

“Courts do things in public,” Judge Smith said in an interview. “That’s the way we maintain our legitimacy. As citizens, we need to know how law enforcement is using this power.”

But most court orders allowing surveillance are so secret, he wrote in a provocative new article, that they might as well be “written in invisible ink.” The article chronicles the rise of a secret docket on a scale that has no parallels in American history.

Gathering the information was frustrating, Judge Smith said. “Even judges have difficulty finding out what other judges are doing,” he said.