Mexico holds its presidential election on July second and recent polls give a slight lead to Felipe Calderon, candidate of the National Action Party, or PAN, the same party of incumbent President Vicente Fox. However, a top expert on Mexico in the United States, Professor George Grayson of the College of William and Mary in Virginia, sees possible trouble ahead no matter who wins.

In a presentation to the Houston World Affairs Council Thursday, Professor Grayson said none of the presidential candidates in Mexico is likely to make the deep structural changes the country needs in order to prosper.

Grayson says the candidate who had been in the lead until recently, former Mexico City Mayor Andres Manuel Lopez Obrador, is the one who would most likely try to move Mexico away from the free-market, free-trade path it has been on for the past two decades.

Critics call Lopez Obrador a populist who would follow the lead of Venezuelan President Hugo Chavez. But Professor Grayson says the candidate of the Party of the Democratic Revolution, or PRD, is his own man, with his own vision.

"Lopez Obrador does not just talk the talk, he walks the walk. He spent five and a half years living with the Chontal Indians and he got up every morning at six and worked with them until sundown. He is personally honest. He has a very austere manner of living. Money does not matter to him. But he believes he has been called to save the Mexican people," he said.

George Grayson, who has written a book about Lopez Obrador called Mexican Messiah, says the P-R-D candidate scares many voters, especially in the Middle Class, because of his detached style and his sometimes harsh rhetoric.

As an example, Grayson notes that the rival PAN scored big with voters running a television ad which used images of Hugo Chavez juxtaposed with images of Lopez Obrador and also had a segment from a speech in which Lopez Obrador insulted President Fox.

"You might not like everything that Vicente Fox, the president, does, but that was over the top in terms of being disrespectful toward the leader of your country. Since the day those ads appeared, Lopez Obrador has begun to drop in the polls," he said.

Polls show the candidate of the Institutional Revolutionary Party, Roberto Madrazo, in a distant third place, but Grayson says he should not be counted out. The PRI, ruled the country for more than 70 years uninterrupted until the victory of Vicente Fox in the year 2000.

The Fox government is widely seen as having failed to produce dramatic change, but because Vicente Fox has operated independent of his party, Grayson says voters do not blame Felipe Calderon or the PAN for any failings they see in Fox. Mexico's economy has also rebounded in the past year, helping to restore the luster of the Fox government.

George Grayson says one potential source of trouble would be a close election result in which Calderon or Madrazo wins. He says Lopez Obrador has criticized the electoral system as favoring the powerful and has disparaged the polls showing him losing ground as part of a conspiracy against him. As a result, Grayson says, his supporters could take to the streets in anger if the official vote tally shows him losing.