Leftist Andres Manuel Lopez Obrador swore himself in as Mexico's "legitimate" president and launched a parallel government, promising to legally limit the power of big corporations and the "neo-fascist oligarchy" that he said now controls Mexico.
"I pledge ... to serve loyally and patriotically as legitimate president of Mexico," Lopez Obrador said during a ceremony on a blustery, bone-chilling Monday afternoon in the capital's main central plaza, the Zocalo -- just 11 days before president-elect Felipe Calderon is sworn in as the nation's legal president.
"I pledge to protect the rights of Mexicans ... and ensure the happiness and welfare of the people," the former Mexico City mayor told an estimated 100,000 supporters -- a smaller crowd than that generated by previous Lopez Obrador events.
The ceremony, which took place on the national holiday commemorating the Mexican Revolution, opened the latest chapter in Lopez Obrador's unsuccessful battle for the presidency.
He claims fraud and dirty campaign tactics were responsible for Calderon's narrow victory in the July 2 vote, and his parallel government could spend the next six years calling for the kind of street protests that have already prompted travel warnings from the US embassy.
Rosario Ibarra, a human rights activist and senator for Lopez Obrador's coalition, placed the red-green-and-white presidential sash across his shoulders. While the action lacks legal recognition, Lopez Obrador hopes to assume the moral leadership of millions of poor Mexicans.
His parallel government, with a 12-member Cabinet, will not collect taxes or try to make laws, and it will rely on donations.
Lopez Obrador plans to spend three days a week in Mexico City and spend the other four days touring Mexico in order "to create the most important citizens' organization in all our history."
But his movement's first action will be to try to prevent Calderon's Dec. 1 inauguration ceremony.
"We are going to make Calderon realize at all times that he is an illegitimate leader," said 55-year-old Lopez Obrador supporter Beatriz Zuniga, an unemployed professor of Latin American studies. "He's got a limited amount of time. This man will not finish his term."
Calderon insisted again on Monday that he will attend his swearing-in ceremony at the national Congress despite Lopez Obrador supporters' threats to disrupt it.