Fernando De la Rua declared a state of siege on Dec. 20, 2001, seizing special powers to deal with rioting and looting. Five protesters were killed and 100 were injured during clashes with police.
The Federal Court of Cassation unanimously ruled Thursday that de la Rua's decision was legitimate and rejected homicide and other charges filed in 2010.
De la Rua served from 1999 to Dec. 2001, when the International Monetary Fund refused to extend more loans and the economy collapsed. The deadly riots that followed forced him to escape by helicopter from the rooftop of the presidential palace.