Answer
Luis Alberto Lacalle was the primary competitor in Tabaré Vázquez's first successful presidential election. Lacalle was a member of the National Party, while Vázquez was a member of the Broad Front. Lacalle had been president of Uruguay from 1990 to 1995, and he was seeking to return to the presidency. Vázquez won the election by a narrow margin, and he was inaugurated as president on March 1, 2005.