* President wins resounding re-election victory
* Exit poll gives her 55 percent of vote, massive lead
* Seen maintaining big spending, interventionist policies
* Worsening global economy could force changes (Recasts throughout, adds fresh quotes, color)
By Helen Popper and Terry Wade
BUENOS AIRES, Oct 23 (Reuters) - Argentina's fiery center-leftist president, Cristina Fernandez, swept to a landslide re-election victory on Sunday, crowning a comeback that seemed unthinkable for much of her turbulent first term.
An exit poll showed Fernandez winning with 55 percent of the vote, about 40 percentage points ahead of her nearest rival, Socialist Hermes Binner.
No Argentine leader has won such a big share of the vote since Gen. Juan Domingo Peron was elected with 62 percent in 1973, and Fernandez's supporters celebrated in downtown Buenos Aires, waving blue-and-white flags and chanting.
If confirmed by official results, the scale of Fernandez's victory would give her a strong mandate to deepen the unconventional and interventionist economic policies that play well with many voters but irritate investors and farmers.
It marks a dramatic change of fortunes for a leader who some critics once said might have to leave power early as angry protests by farmers and middle-class voters battered her approval ratings soon after she took office.
When her husband and predecessor as president, Nestor Kirchner, died a year ago, many thought it spelled the end of the couple's idiosyncratic blend of state intervention, nationalist rhetoric and the championing of human rights.
Instead, it prompted a wave of nostalgia for the best years of Kirchner's 2003-2007 presidency and sympathy for a woman who suddenly seemed more likable.
A skilled orator fond of glamorous clothes and make-up, Fernandez still wears black as she mourns her husband and closest advisor. His image featured heavily in her campaign.
A splintered opposition and brisk economic growth helped Fernandez turn the sympathy vote into solid support.
Despite double-digit inflation and other signs of strain as global conditions worsen, Argentina's economy is growing at about 8 percent a year and has regained some of its glory as the "breadbasket of the world" as grains shipments rise. Unemployment is at a 20-year low.
Voters with memories of the hyperinflation of the late 1980s and a severe economic crisis 10 years ago have good reason to think things could be worse than they are today.
"Crises come and go here and instability's exhausting because you make plans and they keep going to waste," said Marta Rey, 50, a teacher who voted for Fernandez's Peronist party for the first time on Sunday. "It gives me a certain security for my son and for the future."
Fernandez's supporters highlight progress on expanding pensions coverage, child welfare benefits and the construction of schools and homes.
The scale of Fernandez's victory belies fierce opposition to her combative, heavy-handed style -- typical of the Peronist party that has dominated Argentine politics for decades.
"It's a complete mess ... the corruption, the inflation, lies, authoritarianism. We've got used to living like this," said Juan Tofalo, 43, a newspaper vendor in Buenos Aires.
Allegations of corruption and murky dealings have stalked the government for years, although there have been no convictions.
A recent crackdown on economists whose inflation estimates double the official rate of a discredited state statistics agency is typical of Fernandez's controversial methods, who some critics say resemble those of Venezuela's Hugo Chavez.
Businesses are routinely strong-armed into price control agreements -- her main weapon against surging prices -- and deals to increase their exports as the trade surplus dwindles.
When a leading newspaper and cable news channel owned by the Grupo Clarin conglomerate criticized her handling of the farm revolt, Fernandez hit back. The company was stripped of a key operating license and "Clarin Lies" posters appeared across the capital.
In 2008, at the height of the global financial crisis, Fernandez stunned financial markets by nationalizing private pensions. A year later, she fired the head of the central bank when he refused to hand over foreign reserves to pay debt.
Such measures, coupled with high inflation and lax monetary and fiscal policy are dimly viewed on Wall Street, where economists say Latin America's third-biggest economy could be heading for a hard landing as global conditions sour.
Few analysts think she will change course unless she is forced to by a sharp slowdown in neighboring powerhouse Brazil or lower prices for Argentina's key exports of corn and soy.
Fernandez has outlined few concrete policy proposals, vowing only to "deepen the model."
"We know very little (about her plans)," said Mariel Fornoni, a pollster at the Management & Fit consulting firm. "It's turned into a kind of absolute rule. Cristina decides everything." (Additional reporting by Guido Nejamkis and Alejandro Lifschitz; Editing by Kieran Murray)