Carlos Saul Menem governed Argentina for 10 years (since 1989). He's from the Peronist party and he has previously be the governor of La Rioja province. Under his goverment, Argentina's economy underwent deep changes, it was opened to this globalized world. His government will be remembered for his corruption. Currently, Carlos Menem if in jail (well, in home-arrest because he's over 70) for selling arms to Croatia and Ecuador with fake destinations.
He was followed in the presidency by Fernando de la Rua.