The main purpose of this legislation is to prevent the U.S. government from using military force in or against Mexico without explicit approval from Congress. It aims to ensure that any military action in this context is subject to proper legislative oversight, aligning with the principles of the War Powers Resolution. The key provisions of this law state that from the date it is enacted until December 31, 2026, no federal funds can be used for military operations in Mexico unless Congress has either declared war or provided specific authorization for such actions.