The Congressional Power of the Purse Act strengthens Congress's control over federal spending by restricting the President's ability to withhold, delay, or redirect appropriated funds, while expanding congressional oversight of the executive branch's budget decisions. The legislation eliminates expedited presidential rescission procedures, requires agencies to obligate funds promptly and notify Congress of delays, enhances the Comptroller General's authority to investigate spending violations and sue in federal court, and establishes penalties including fines and imprisonment for federal officials who willfully withhold budget information. The bill also imposes new transparency requirements on emergency spending, mandates detailed reporting on budget authority management and Antideficiency Act violations, and creates a new Inspector General for the Office of Management and Budget. Additionally, the legislation establishes a congressional approval process for presidential national emergency declarations, with emergency powers automatically expiring after 45 days unless Congress votes to renew them, and requires the President to submit detailed emergency reports and sensitive contingency plans to Congress for oversight. These provisions take effect immediately for most requirements, with enhanced presidential budget reporting required beginning in fiscal year 2027 and OMB Inspector General establishment within 120 days.