President-elect Mauricio Macri's promises to revitalize Argentina's sagging economy with free-market reforms and improve strained relations with the United States resonated with voters, carrying him to a historic win that ended 12 years of often-conflictive rule by President Cristina Fernandez and her late husband.
"Today is a historic day," Macri said while his supporters celebrated. "It's the changing of an era."
With 98 percent of the vote counted from Sunday's election, Macri had 51.5 percent support compared to 48.5 percent for ruling party candidate Daniel Scioli, Fernandez's hand-chosen successor.
But when the business-friendly opposition candidate takes office Dec. 10, he will inherit a country with around 30 percent inflation, near-zero economic growth and entrenched government social spending that private economists warn is not sustainable. He 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."
Macri's family is one of the wealthiest in the country, and he rose to fame as president of the popular Boca Juniors soccer club. On the campaign trail, he sometimes talked about being kidnapped in the early 1990s, an experience he said helped him understand the needs of others and he credits with pushing him into politics.
Later, as major of Buenos Aires, he was known for a technocratic manner that stressed efficiency over style.
Addressing thousands of supporters late Sunday, Macri said his presidency would not be about "revenge" or "settling scores," but rather helping the country progress.
"I feel so happy because today we put an end to the mafia" of ruling party rule, said Felisa Sanchez, a Macri supporter waving an Argentine flag. "They claimed to be Robin Hood helping the poor with social welfare plans when the poor are really helped with jobs and education."
But fulfilling his campaign promise to reform Argentina's economy may prove difficult.
Macri, 56, has pledged to lift unpopular controls on the purchase of U.S. dollars and thus eliminate a booming black market for currency exchange. Doing that would likely lead to a sharp devaluation of the Argentine peso. With foreign reserves around $26 billion, low for such a large economy, the government would desperately need an immediate infusion of dollars.
That could come from many different places, but ultimately would require structural changes to a largely protectionist economy, solving a debt spat and developing warmer relations with the United States and other nations.
He has also vowed to jumpstart the economy by lifting many tariffs, lowering taxes and attracting foreign investment. He promised to solve a long-standing New York court fight with creditors in the U.S. who Fernandez called "vultures" and has refused to negotiate with, which kept Argentina on the margins of international credit markets.
Macri's win signals a clear end to the era of Fernandez and her late husband. During their years in office, the power couple gained popularity by spending heavily on programs for the poor, raising tariffs to protect local economies and passing several progressive laws, including the legalization of gay marriage in 2010.
"This is a painful day for Argentines," said Rocio Robador, a government supporter who was crying in the iconic Plaza de Mayo. Robador, 36, said she was able to get pregnant and have a child thanks to a government that helps poor women get fertility treatments.
Macri frequently repelled Scioli's attempts to paint him as a 1990s neoliberal, saying he would lead with "21st century development" as opposed to "21st century socialism."