BUENOS AIRES, Argentina (AP) -- President Cristina Fernandez's governing bloc held onto control of Congress in Sunday's congressional elections, but the results buried hopes of changing the constitution to let her run for a third term and a former loyalist proved himself a political threat.
The president's former Cabinet chief, Sergio Massa, beat the candidate that Fernandez hand-picked to lead her slate for Congress, Martin Insaurralde, by a decisive 12-point margin in Buenos Aires province, where 37 percent of Argentina's voters live.
With 72 percent of the votes counted nationwide, the governing Front for Victory won 33 percent of the congressional votes overall, far short of the 54 percent that Fernandez carried in her re-election in 2011.
Cabinet Chief Juan Manuel Abal Medina predicted that when all the votes were in, the front would gain five seats in the 257-seat Chamber of Deputies and maintain a "comfortable majority" in the 72-member senate.
The Front for Victory remains the only nationwide political force and still holds more seats in Congress than any other bloc.
But its losses in Argentina's most populous districts suggested growing unhappiness and a weakened presidency. And the increasing appeal of Fernandez's rivals elected Sunday could pose new threats to her all-or-nothing style of governing.
The president's opponents won more than enough seats to block any constitutional changes, ruling out a "re-re-election" in 2015. Without that threat, it might prove harder for Fernandez to keep rivals in check as Argentines begin marking the end of a government that she and her husband, the late President Nestor Kirchner, have led for a decade.
Massa, whose calls for consensus and rising popularity have already peeled away some Fernandez loyalists, will be sworn in Dec. 10 as a deputy in Congress after receiving the most votes of any politician running Sunday.
"We accept our differences, plurality, and as our Pope Francis says, harmony, which is the best way to build our society," Massa said Sunday night in calling on all Argentine politicians to "please listen to the message of the people."
For the moment at least, the results position Massa to make a presidential run in 2015.
"This is an overwhelming response by the people to our times," said Dario Giustozzi, a member of Massa's Renewal Front who also won a seat in Congress. "This is the end of an era, a new space. Now the people have a place where they can be heard."
Massa, however, will no longer be the successful mayor of the wealthy Tigre municipality, where many of Argentina's rich and famous live in gated communities. Now he'll need to make his voice heard while leading the third-largest force in Congress, with about 19 seats, compared to 131 for the ruling bloc.
Before Fernandez, 60, was diagnosed with a head injury Oct. 6, she had appeared with Insaurralde at every major campaign event, sometimes doing all the talking.
But since her skull surgery, she has remained in seclusion, a very unusual situation for a country accustomed to seeing her on television every day. While her doctors say her condition is improving, they ordered her to rest for a month and avoid any stress.
Her vice president, Amado Boudou, is nominally in charge while she recuperates, but even top ministers have struggled to describe how decisions are being made, contradicting each other about how much she's following the news. She was unable to vote or visit Kirchner's tomb Sunday, which was the third anniversary of his death from a heart attack.
With Boudou's political future clouded by corruption investigations, Fernandez could now spend her last two years struggling to keep rivals in line during an intense succession battle within the always fractious Peronist party, to which her center-left Front for Victory belongs.
Along with Massa, would-be presidents include the governor of Buenos Aires province, Daniel Scioli, and the mayor of the capital of Buenos Aires, Mauricio Macri. Both are seen as more business-friendly and centrist than Fernandez.
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