NUEVO LAREDO, Mexico -- If leading presidential contender Andres Manuel Lopez Obrador wants to make good on his promise to stand Mexican politics on its head, he will need a lot more supporters like Vicente San Miguel.
San Miguel was one of thousands of Lopez Obrador fans who cheered the former Mexico City mayor last weekend as he toured violence-racked cities along the Texas border.
It was a surprising turnout: Opposing parties hold nearly every local, state, and federal office in this region.
''I don't follow politics much. I've never even voted," said San Miguel, a 35-year-old engineer who came to a campaign appearance. ''But I really like this guy. I like his integrity and what he's done in Mexico City. . . . I didn't want to miss this."
Like President Vicente Fox, whose victory in 2000 broke the 71-year reign of the Institutional Revolutionary Party, or PRI, Lopez Obrador hopes to win next year's presidential election with the promise of change. He also needs a large voter turnout to have a chance against the political machine of PRI.
So with no money to spend on television or radio advertising and a pledge to refuse cash from special interests, Lopez Obrador plays the little guy standing up to the corrupt and powerful. He makes his appeals at gymnasiums, rented halls, and on the back of pickup trucks.
He scares some with his leftist talk about putting the poor first and paying monthly stipends to single mothers and senior citizens.
But with half the country's 100-million-plus people living in poverty, there is a big market for what he is selling. If the election were held today, polls indicate that he would win.
During a caravan recently along Mexico's northeast border, he preached humility, austerity, and populism. He said he would decline presidential jets and fly commercial, end fat pensions for millionaire ex-presidents, and lower prices for electricity, gasoline, and natural gas.
He mocked high-ranking politicians who bill the government for medical treatments in the United States and promised to make them wait in line at public clinics like everybody else. He condemned stagnant wages that drive Mexicans to the United States, and promised tariff protections for farmers.
His support is not limited to the poor, many of whom attended his rallies in castoff clothing. His political base in Mexico City includes a mix of limousine liberals and the working class.
And then there are upwardly mobile types such as San Miguel, who say they are lukewarm about Lopez Obrador's Democratic Revolution Party but inspired by a man who asserts he can save enough money by ending corruption in order to build up the country.
''Fox shattered corruption into big pieces," he said. ''This guy will finish the job."
That belief, in defiance of Mexican history and human nature, echoes a popular message on the black-and-yellow T-shirts being sold in the Lopez Obrador barnstorm: ''Que nadie nos robe la esperanza." Loose translation: ''They can steal everything but hope."
Supporters say there is reason to expect miracles from Lopez Obrador, given his humiliation of the political elite this past spring.
While still mayor, he was accused of disobeying a judge's order in a minor legal dispute. With the support of Fox, lawmakers voted to strip Lopez Obrador of his political immunity, solemnly intoning the rule of law, and, by coincidence, in effect barring him from running for president.
A million or so residents protested, and Fox stood down, dumped the attorney general and dropped the case. Lopez Obrador, who quit as mayor to campaign full time, relished retelling the story during campaign speeches.
People five-deep pressed on him, reaching out to his hands and shoulders, holding babies and toddlers out to him, whispering messages and encouragement, giving hugs, and kissing his cheek.
The PRI primary is scheduled for mid-November, and Madrazo faces a strong challenge from Arturo Montiel, who just ended his term as governor of Mexico state.
The National Action Party, or PAN, which brought Fox into office, finished its second round of primaries last week, with Felipe Calderon -- Fox's former energy secretary and a former PAN party president -- winning both contests. Second-place finisher Santiago Creel, who was Fox's secretary of interior, said he would continue campaigning through the party's third primary, scheduled for Mexico's northern and western states Oct. 23.
Lopez Obrador ended the weekend campaign trip at the airport in Matamoros, waiting to board a 9:35 a.m. flight back to Mexico City. For a moment, he sat undisturbed. Then, one by one, well-wishers lined up to have cellphone photos taken of themselves sitting next to him.
Once on the plane, he and his son found their seats, in economy class.