“There's, you know, a review or sort of relook at the employment guidance, which is more about the commander of STRATCOM and his responsibilities and [the defense] secretary's authorities, etcetera,” said Undersecretary of Defense for Policy Elbridge Colby.

The classified strategy informs nuclear options for the commander in chief during crises.

According to the sources, the Pentagon has begun drafting a new US nuclear strategy that "emphasizes the possible use of shorter-range tactical weapons"