Empty chair and slurs mar Mexico election debate

MEXICO CITY (Reuters) - Mexico's presidential candidates tore into each other on Tuesday in a televised debate with some tough rhetoric also aimed at an empty chair set aside for a leftist front runner who refused to take part.

Andres Manuel Lopez Obrador, a former Mexico City mayor who promises heavy spending on the poor and until recently held a big lead over his rivals, stayed away from the first debate of the campaign despite suffering a sudden slump in opinion polls.

His main rival, Felipe Calderon of the ruling conservative party, tried to take advantage of Lopez Obrador's absence by saying he had nothing to offer voters.

"He didn't come because he does not have viable proposals," Calderon said.

Calderon's popularity has recently surged and he won a major boost earlier on Tuesday when a closely-watched opinion poll showed him leading for the first time with 38 percent support and Lopez Obrador trailing with 35 percent.

He hoped to gain even more ground with a strong performance in the debate, the first of two scheduled before the July 2 election, and calmly laid out his main proposals on creating jobs and making Mexico's crucial energy sector more efficient.

But he also got into a verbal fight with the third-placed candidate, Roberto Madrazo of the Institutional Revolutionary Party which ruled Mexico for 71 years before it was toppled in historic elections in 2000.

Calderon and Madrazo repeatedly accused each other of corruption and incompetence, while two minor candidates tried to boost their own chances with sharp criticisms of Mexico's main parties and promises to start afresh.

There were no new proposals from any of the candidates, however.

The election will determine whether Mexico joins a growing number of Latin American nations moving to the political left or whether it stays firmly allied to the United States, its northern neighbor and dominant trading partner.

Lopez Obrador, 52, has promised to end two decades of Washington-backed free market reforms and pump money into welfare programs and infrastructure projects.

Similar policies won him huge support when he was mayor of Mexico City and he had consistently led presidential opinion polls for the last three years despite fears among business leaders that he might ruin Mexico's economic stability. Only last month, he declared he was "politically indestructible."

But that changed dramatically in the past month. Lopez Obrador lost support by squabbling with President Vicente Fox and refusing to join the debate, and his rivals took advantage by rolling out a series of aggressive campaign ads.

He alienated voters by angrily telling the popular Fox to "shut up" and comparing him to a "chachalaca," a wild bird known for its loud, irritating squawk.

Fox is barred under the constitution from seeking reelection but Lopez Obrador's attack appeared to boost Calderon, the ruling National Action Party's candidate.