“The Army Field Manual can be reviewed every three years. That might be the only weak part of it,” Feinstein said, but she had no concern “right now” that this could occur. And even in that case, McCain and Feinstein’s law prohibits any changes in the field manual that would involve the use or threat of force.

National security and legal experts, on the other hand, believe that the law is clear—and almost airtight.

“Many people have had the instinct that torture was convenient, or effective, or acceptable. And we, the American people, Congress, and the world at large as airtight a prohibition as is legally possible,” said David Cole, the national legal director of the American Civil Liberties Union. “[The Trump administration] would have to change the field manual, overcome extraordinary resistance in the military, make it public, thereby bringing on them the uniform criticism of the world.”