The Office of Legal Counsel (OLC) is a division of the U.S. Department of Justice that provides authoritative legal advice to the president and the heads of executive branch agencies. OLC opinions bind all executive branch agencies and departments, meaning they effectively function as law within the executive branch. However, OLC opinions do not bind federal courts. When OLC declares a statute unconstitutional, the executive branch no longer enforces or complies with it. The OLC has issued controversial opinions in the past, including memos justifying warrantless wiretapping after September 11.