Yanina Mendoza doesn't seem a natural voter for opposition leader Mauricio Macri, a member of one of Argentina's richest families who is running for president on pro-market credentials.

The 24-year-old single mother makes about $1,200 a month as a maid and lives in a rough area of Ciudadela, a city about 12 miles (20 kilometers) west of Buenos Aires. Since the country's return to democracy in 1983, her Tres de Febrero neighborhood has traditionally backed leaders from within Peronism, a working class movement founded by three-time President Juan Peron.

That changed Oct. 25, when millions like Mendoza in the vast Buenos Aires province shook up the political landscape by voting for Macri and forcing a Nov. 22 runoff against Daniel Scioli, the governing party candidate. Scioli has been governor of the province for eight years and is the chosen successor of outgoing President Cristina Fernandez, the current standard-bearer of Peronism.

"I hope Macri can be a real change," Mendoza said, emerging with her 1-year-old daughter from an apartment building with bars on the windows. "Every day there is more crime, and we need more police."

Macri's surprisingly strong first-round finish was based largely on his robust showing in Buenos Aires province, whose 15 million residents make up 40 percent of the country's population and is larger geographically than Italy or the U.S. state of Arizona. The province includes coastline, farmland and a seemingly endless sprawl of densely populated urban centers around the city of Buenos Aires, which is part of the province.

Whoever wins the province will likely be the South American nation's next president, a reality that has prompted a mad scramble by the candidates, along with political observers and demographers, to understand what happened last month.

For months, polls predicted Scioli would win the election by 10 points or more. But instead, he garnered 37 percent, barely ahead of Macri at 34 percent. The biggest surprise was in this province: Scioli got 3.5 million votes while Macri got 3.1 million, a shocking result that analysts can only interpret with the old adage that "all politics are local."

Scioli is finishing his second term as governor of the province while Macri is doing the same as mayor of the city of Buenos Aires, giving voters firsthand experience by which to judge them.

"There are many problems in the province that haven't been solved," said Roberto Chiti, an analyst with the consulting firm Diagnostico Politico. "Some go beyond Scioli's control, but not all."

The list of gripes is long: crumbling schools, dilapidated public hospitals and periodic flooding, such as in August, when heavy rains forced tens of thousands to evacuate their homes.

But the most pressing issue, often the first thing people mention on the streets, is crime. Just how bad things are is anybody's guess because the Ministry of Justice stopped publishing national crime statistics in 2009.

The feel in neighborhoods like Tres de Febrero explains a lot. Heavily armed gendarmes wearing bullet-proof vests guard dozens of checkpoints. Businesses, and many of the modest cement-block homes, have barred windows. Stories abound about break-ins, armed heists and kidnappings.

"I look out on the street and see people getting robbed every day," said Guillermo Gamarra, who owns a corner store whose front is lined with metal bars. Gamarra said he was leaning toward Macri after voting last month for Sergio Massa, a former ruling party loyalist who broke ranks to form his own movement.

Many residents here travel each day to work in the city of Buenos Aires. Comparisons are arguably unfair because the capital is far richer, and represents only a fraction of the province with its 3 million people. But that doesn't stop commuters from seeing cleaner streets, more orderly traffic and a heavier police presence, and wanting that for their own neighborhoods.

The Tres de Febrero neighborhood, which has about 340,000 people, gave a slight majority to Macri along with opposition candidates for governor and mayor.

Still, it's too early to write off Scioli. Fernandez, the president who backs him, has a strong following among the poor and the ruling party's reach runs deep.

In Tres de Febrero recently, the campaign signs pictured either Scioli or Massa, considered a Peronist. No signs were of Macri, who many fear will scale back social welfare spending despite promises not to.

"People around here don't have anything," said Natalia Navarro, a single mother of four who receives about $125 a month from the government. "Macri makes promises but I don't think he'll do anything for the poor."

___

Associated Press writer Debora Rey in Buenos Aires contributed to this report.

___

Peter Prengaman on Twitter: http://twitter.com/peterprengaman