ACAPULCO, Mexico (Reuters) - Mexican financiers and politicians blasted populism at a top banking conference this week in a thinly veiled attack on the frontrunner for the 2018 presidential election - but some worry they overdid it and may have played right into his hands.

Mexican politician Andres Manuel Lopez Obrador, leader of the National Regeneration Movement (MORENA) greets supporters during a meeting at Plaza Zaragoza in Monterrey, Mexico February 25, 2017. REUTERS/Daniel Becerril - RTS10BPO

The chosen theme of the annual meeting at the beach resort of Acapulco was “liberalism versus populism,” with President Enrique Pena Nieto, senior ministers, former U.S. Treasury Secretary Larry Summers and ex-Secretary of State Colin Powell among the grandees squarely lined up on one side.

Without a voice but very much on the lips of the Mexicans was Andres Manuel Lopez Obrador, a leftist former Mexico City mayor and twice presidential runner-up whose relentless campaigning has put him in contention to go one better in 2018.

Lopez Obrador’s broadsides against corruption and inequality sting a Mexican political establishment tainted by allegations of graft, even as U.S. President Donald Trump’s populist jabs at Mexico have generated some sympathy for Pena Nieto at home.

After extensive security checks in this fabled tourist destination that today struggles with gang violence, Mexican bankers heard speakers condemn what Pena Nieto called the “easy escapes” and “magical solutions” of populism.

Still, mindful of Trump’s shock victory across the border in November, several bankers said they would have liked to hear from populists, and for their lobby, the Mexican Banking Association (ABM), to avoid choosing sides.

“You have to be balanced and objective. Putting liberalism as all good and populism as all bad doesn’t represent what all banks want,” said Raul Martinez-Ostos, chief executive officer and president of Barclays Mexico.

The possibility of a Lopez Obrador victory in July 2018 is already causing nervousness among economists.

Luis Robles, the ABM’s president and chairman of Banco Bilbao Vizcaya Argentaria’s Mexico unit, Bancomer, said the point was not to pick sides, but to analyze a phenomenon.

Robles said the ABM did not invite Lopez Obrador because “he’s a politician and this is a banking convention.”

That did not stop officials including Finance Minister Jose Antonio Meade from warning about people urging Mexicans to “return to the past, isolate ourselves and ignore technological change.”

Pena Nieto was invited, not as a politician but to represent a Mexican institution, Robles said. Even if debate had been the goal, it would not have been possible, he argued: “It’s hard to debate something that’s false by definition: false premises, alternative realities that aren’t objective.”

But other bankers said such voices needed to be heard.

“Populist governments have proven they don’t work, and they can hurt lots of countries, including ours,” said Oscar Dominguez, a senior Mexico executive at Volkswagen Financial Services. “Still, it makes a lot of sense to listen to what they have to say. That voice was missing from the conference.”

Lopez Obrador respects the decisions of the ABM, said his spokesman Cesar Yanez.

“We aren’t fighting with any constituency in this country -not with bankers, not with businessmen,” he said. “We need all of them to move our country forward.”

(Corrects title of Barclays executive in paragraph 7)