PREVIEW-Argentine midterm vote to kick off next presidential race
BUENOS AIRES, Oct 24 (Reuters) - Argentina's legislative elections on Sunday will serve as a starting line for the race to succeed President Cristina Fernandez in 2015, with her support in Congress too low for allies to push through constitutional changes to allow her to run again.
Recovering from surgery to remove blood from the surface of her brain this month after she fell and hit her head, Fernandez, 60, has been unable to campaign for her candidates in the final stretch before the midterm vote.
Polls show her alliance could lose the majority it has had in both chambers of Congress since 2011, when Fernandez won a second term on promises of increasing the government's role in Latin America's third biggest economy.
In play on Sunday and in 2015 is future policy in one of the world's top grains exporters at a time of booming world food demand. Growers and other investors have long feuded with Fernandez over her interventionist policies.
Argentina also emerging as a potential oil and natural gas exporter. Its Vaca Muerta shale formation in Patagonia is expected to be one of the biggest of its kind, and it needs billions of dollars of development investment.
Candidates backed by Fernandez won just 26 percent of the vote in a midterm primary vote in August, half of what her alliance got in 2011, and her handpicked congressional candidate had a poor showing in the must-win province of Buenos Aires.
Some legislators had said they wanted a constitutional amendment to allow Fernandez to run for a third term, but those hopes were dashed by the poor showing in the primary. To push through reform, they would need two-thirds support in both houses.
In Sunday's midterm, voters will choose half of the lower house of Congress and a third of the Senate.
Unless Fernandez's allies defy all the polls and win her a strong majority, the vote will almost certainly end speculation about constitutional reforms and start a succession struggle within Fernandez's branch of the Peronist party.
Stocks and bonds have rallied on investors' hopes of market-friendly policy changes ahead.
The blue-chip Merval stock index is up nearly 50 percent since the Aug. 12 primary, and analysts see more gains ahead if Fernandez's candidates get thumped again on Sunday.
"The midterm is the beginning of the end of the Kirchner-Fernandez era," said Alberto Bernal, head of emerging markets research at Bulltick Capital Markets in Miami, referring to the president and her late husband, Nestor Kirchner, who preceded her as Argentina's leader.
"The markets are hoping for regime change because nothing less than that can get the economy back on track," Bernal added.
Presidential hopeful Sergio Massa, the business-friendly mayor of Tigre, near the capital, could broaden his 5 percentage point advantage in opinion polls over rival Martin Insaurralde, Fernandez's handpicked candidate in the strategic province of Buenos Aires.
If he does so, Massa - who vows to fight crime, combat inflation and improve farm profits - may be well positioned to run for president. But Argentine history shows midterm victors are rarely able to sustain momentum and clinch the nomination.
A dark horse could appear over the two years ahead, as was the case with former President Carlos Menem, who burst onto the scene in 1989, and Kirchner in 2003.
The vote on Sunday will also test the support of presidential hopefuls such as Julio Cobos, a Radical Party member from Mendoza; Hermes Binner, a socialist from Santa Fe; Buenos Aires Governor Daniel Scioli, an ally of the president despite his market-friendly views; and the capital city's mayor, Mauricio Macri.
Fernandez, meanwhile, has been weakened by fears over the economy. Inflation is clocked by private economists at around 25 percent, while foreign exchange controls have cut access to U.S. dollars, Argentina's traditional currency of choice for savers.
Import controls make it hard for some businesses to get basic supplies needed for production.
Farmers say the limits that the government puts on corn and wheat exports kill profits along with a 35 percent tax slapped on soybean shipments.
(Reporting by Hugh Bronstein; Editing by Kieran Murray and Eric Beech)