Section 683 of the Impoundment Control Act of 1974 states that “whenever the President determines ... that such budget authority should be rescinded … [or] reserved from obligation for such fiscal year, the President shall transmit to both Houses of Congress a special message” to that effect with an explanation. The Congress then has 45 calendar days to concur, or the funds are to be “made available for obligation” and “may not be proposed for rescission again.”