BUENOS AIRES (Reuters) - The savvy young mayor of Tigre, Argentina, has fostered a real estate boom, tightened security and brought celebrities to town, boosting his image to the point where pollsters say he poses a challenge to the ruling government.
Sergio Massa, 41, served as President Cristina Fernandez's cabinet chief for less than a year between 2008 and 2009. He resigned after she stepped up state intervention in the economy, but he stuck with the ruling party during the 2011 elections.
This year, however, is different.
Last week, the charming, cocky politician broke ranks with the government by signing up his own coalition to compete in October's congressional vote.
Now he must decide if he will run for Congress himself or put a lesser-known ally at the top of his coalition's ticket to avoid a head-on collision with Fernandez.
Massa is one of the most popular politicians in Argentina, polling well ahead of most other leaders and several percentage points above Fernandez, whose approval ratings have sunk since she was re-elected in late 2011.
Tigre lies just 19 miles (32 km) north of Buenos Aires and is home to about 380,000. The mayor has overseen its transformation from a shabby satellite city to a vibrant tourist destination where upscale housing developments proliferate along picturesque waterways.
Massa has close ties to business and was re-elected as mayor in 2011 with 73 percent of the vote.
He has studiously avoided any criticism of Fernandez to widen his appeal in an increasingly polarized country.
"Massa has support among people who back the government and among the opposition ... he has the power to defeat Cristina's government," said political analyst Carlos Germano. "The business world is betting on him."
Saturday is the deadline to register candidacies for the lower house of Congress in Buenos Aires province. A slew of parties will compete and they win seats proportionally, depending on how many votes they get province-wide.
Germano said polls show Massa has about 40 percent voter support in densely populated Buenos Aires province, where Tigre is located and where four in every 10 Argentines vote.
The province will be a crucial battleground for the ruling coalition in the mid-term elections because its candidates are unlikely to prevail in the city of Buenos Aires or other major districts such as Santa Fe, Cordoba and Mendoza provinces.
In October, 24 of 72 upper house Senate seats will be contested along with 127 of the lower house's 257 seats. Fernandez controls Congress now, but with so many of those posts in play, the legislature will be up for grabs.
Some of the president's allies in Congress want to push for a constitutional reform that would allow her to run for a third term in 2015. But if Massa steps into the ring in October, he could siphon votes off the ruling party, thereby dashing those hopes.
Fernandez has said she has no intention of trying to reform the country's charter, but her supporters encourage the idea - particularly because she has no clear successor.
Massa is eyeing the presidency himself, aides say.
"If Massa wins now, he will be very well-positioned for the presidential election (in 2015)," a person who works closely with the mayor said on condition of anonymity.
Massa declined to be interviewed on the subject.
Both Massa and Fernandez are members of the splintered Peronist party that has dominated Argentine politics since the 1940s, but Massa heads the new "Front for Renewal" movement that groups about 16 mayors in Buenos Aires province.
He is two courses away from finishing a long-pending law degree and people close to him say he is habitually tardy.
Massa had a close, playful relationship with journalists when he was cabinet chief - an anomaly under Fernandez and her predecessor and late husband, Nestor Kirchner, who rarely gave interviews or press conferences.
According to his aides, Massa tried to encourage Fernandez to take market-friendly steps such as cleaning up Argentina's discredited official inflation statistics and reaching a deal with "holdout" creditors who rejected the country's 2005 debt restructuring, after a damaging $100 billion default in 2002.
But Fernandez did not follow this advice and adopted more interventionist policies instead, so Massa decided to resign.
"He went to work with Cristina because Kirchner asked him to ... but he was a fish out of water," another of Massa's allies said.
Massa has turned Tigre's image around by fighting crime, promoting ecotourism in the surrounding river delta and organizing high-profile events, including a private tennis exhibition in which Swiss star Roger Federer played last year.
Federico Weil heads construction company TGLT, which is developing in Tigre a multimillion-dollar housing complex with private docks called Venice. He says the city has come into its own and is now seen as a desirable place to live.
"There's an investment-friendly environment. And because the municipality knows money is being made, they make you give something back in terms of infrastructure, opening streets or the like," Weil said.
Although Massa is widely believed to favour a free-market approach, he has kept quiet as Fernandez bolstered the state's role in the economy, nationalizing the country's top energy company YPF and restricting imports, among other measures.
But his apparently successful strategy of not making waves and remaining above the fray may be tested in coming months.
Interior Minister Florencio Randazzo recently rebuked Massa for his silence, telling reporters: "The truth is I don't know what Massa thinks. You'd have to ask him."
Writing by Hilary Burke