What does the Posse Comitatus Act prohibit?

The Posse Comitatus Act specifically prohibits the use of the U.S. Army and Air Force for the enforcement of domestic laws, which includes the enforcement of domestic policies. This act was enacted in 1878 and reflects the principle of civilian control over the military, ensuring that military forces do not interfere with civilian law enforcement responsibilities.

Under this act, military intervention in domestic affairs is limited, emphasizing that law enforcement remains the responsibility of state and local authorities. While there are exceptions and specific circumstances under which military assistance can be provided, the general rule is that active duty military personnel cannot be used to enforce laws or policies in a domestic context.

This understanding helps clarify the implications of the other options. The deployment of the U.S. Coast Guard is not subject to the same restrictions as the Army and Air Force, particularly in emergency situations. Additionally, while the act restricts domestic deployment of the Army, it does not completely prohibit all military involvement in crises, as demonstrated by other means and forces. Hence, option A correctly summarizes the primary restriction imposed by the Posse Comitatus Act.