PANAMA CITY, Panama -- PANAMA CITY, PanamaPresident Ricardo Martinelli dislikes the politician elected as his vice president. He’s belittled his courage, exhorted him to resign and slapped a $30 million libel suit against him.

Martinelli’s feud with Vice President Juan Carlos Varela is just one chapter in the tale of a onetime supermarket tycoon with an energetic and sometimes erratic style who is upending traditional politics in Panama.

Even his friends describe Martinelli as impatient, occasionally discourteous, and given to outbursts.

Yet his tenacious drive is also transforming the capital of this country, with its growing number of 60- and 70-story oceanfront high-rises and namesake canal that is crucial to world trade. Workers are rushing to build a 9-mile-long metro rail line, which will be partly underground. Work should be done in 2014 on the $1.8 billion system, the first subway in Central America.

The project has helped Martinelli rebound in popularity from a brief free fall earlier this year caused partly by his rupture with the vice president.

When Martinelli, 60, came to office in 2009, he seemed to be on the cusp of a trend of Latin American voters turning to business tycoons for their administrative acumen. In Chile, voters in 2010 elected Sebastian Pinera, an airline and television magnate, to lead that country.

But the skills needed for business decisions do not always translate into the political arena, a fact that seems to be underscored with the case of Martinelli, who is in the third year of a five-year term.

“Perhaps what makes some people think he’s rude, a jerk and impetuous is that he’s trying to do a lot,” said lawmaker Jose Munoz Molina, a former president of the National Assembly and a close friend of Martinelli’s. “When you are in business, you want things to move fast.

“In Panama, there’s a lot of bureaucracy,” he said. “To do something, you have to go through, like, 20 steps. This puts the president in a bad mood.”

To win election in 2009, Martinelli, who heads the relatively young Democratic Change party, entered into a political marriage with Varela, head of the Panamenista Party, a long-established party. The implicit accord was that Martinelli would serve a term, then Varela would run for president in 2014 with the support of Martinelli’s party.

But after 26 months, the accord faltered. Martinelli fired Varela from his concurrent post as foreign minister in August 2011, and members of Varela’s party started leaving the administration.

Tensions between the two boiled over in May as an Italian bribery scandal cast its shadow over Panama. A court case in Italy revealed allegations that an aide to former President Silvio Berlusconi had paid bribes on behalf of an Italian company, Finmeccanica, for some $250 million in contracts in Panama. Martinelli and Berlusconi, both right-wing populists who’d entered politics after building business empires, are fast friends.

On May 9, Martinelli’s lawyer filed a libel suit over Varela’s allegations that Martinelli had pocketed $30 million from a Berlusconi confidant, Valter Lavitola, who is now imprisoned in Italy. The suit seeks $30 million in damages. That same day, Martinelli exhorted Varela to “be a man” and quit the vice presidency.