Alfonsín continued as the leader of the UCR and opposed the presidency of Carlos Menem. He initiated the Pact of Olivos with Menem in order to negotiate the terms for the 1994 amendment of the Argentine Constitution. Fernando de la Rúa led a faction of the UCR that opposed the pact, and eventually became president in 1999. Following de la Rúa's resignation during the December 2001 riots, Alfonsín's faction provided the support needed for the Peronist Eduardo Duhalde to be appointed president by the Congress. He died of lung cancer on 31 March 2009, at the age of 82, and was given a large state funeral.