Opposition candidate Mauricio Macri won Argentina's presidential election on Sunday, marking an end to the left-leaning and often-combative era of President Cristina Fernandez, who, along with her late husband, dominated the country's political scene for 12 years and rewrote its social contract. With 98% of the vote counted from Sunday's election, Macri had 51.5% support compared to 48.5% for ruling party candidate Daniel Scioli, Fernandez's hand-chosen successor. Scioli conceded defeat and Macri claimed victory. "Today is a historic day," Macri crowed while his supporters celebrated. "It's the changing of an era."
Macri's promises to revitalize Argentina's sagging economy with free-market reforms and improve strained relations with the United States resonated with voters. But when the business-friendly opposition candidate takes office Dec. 10, he will inherit a country with around 30% inflation, near-zero economic growth and entrenched government social spending that private economists warn is not sustainable. Macri, the outgoing mayor of Buenos Aires, also lacks majorities in either chamber of Congress to pass his deep reforms. "Macri will begin his mandate in a difficult political position," wrote Daniel Kerner from the Eurasia Group, a political risk consultancy. "He will have to make difficult economic adjustments and face serious political constraints." (Read more Cristina Kirchner stories.)