The Interstate Agreement on Detainers, a compact authorized by federal statute, provides a simple procedure for transferring custody of prisoners between states. Because the federal government annually seeks to prosecute thousands of prisoners already in state custody, it joined the IAD in 1970 to get the benefit of this unified procedure. When it joined, it did so as a "state" for purposes of the agreement, and exempted itself from only two provisions (which aren't relevant here). One of the provisions that the federal government decided not to exempt itself from, Article IV(a), allows the governor of the sending state to deny any request made by a receiving state to transfer a prisoner. In September of 2010, Jason Pleau offered to plead guilty to robbery and murder charges in Rhode Island in exchange for life in prison without parole, the harshest sentence that state's law allows. Pleau's crimes also allegedly violated federal law, however, and the U.S. government wanted to prosecute Pleau itself in order to seek the death penalty. The federal government thus sought custody through the IAD by filing for the little-known writ of habeas corpus ad prosequendum ("show me the body for prosecution"). The governor of Rhode Island, Lincoln Chafee, disapproves of the death penalty and used his authority under the IAD's Article IV(a) to deny the federal request. A federal district court, later affirmed by the U.S. Court of Appeals for the First Circuit, overruled Chafee's denial, stating that the Supremacy Clause prevented the governor from interfering