Who ran the Catholic Church after John Paul II died and before Benedict XVI was elected?

Answer

During an interregnum (Latin: “between reigns”), the day-to-day business of the Church is administered by the cardinal camerlengo (chamberlain). The camerlengo during the interregnum of 2005 was Eduardo Cardinal Martinez Somalo. The camerlengo does not make any decisions that are not of immediate necessity to the administration of the Church. Any decision that is not urgent to the running of the Church is postponed until a new pope is elected.