López Obrador, speaking in calm, measured tones, called for his supporters to gather en masse this Saturday in Mexico's large downtown square, El Zocalo.
López Obrador plans to outline a series of "inconsistencies" that he says affected the outcome of the race and will form the basis of his request to a special elections court for a recount.
"Today, no one can proclaim that they are the winner," López Obrador said.
Mexico has been riven by tensions about the outcome of the race, which pitted the populist López Obrador against Calderón, who promised continuity with outgoing President Vicente Fox. López Obrador has said "the stability of the country" depends on the count and has threatened to mobilize hundreds of thousands of supporters in street protests.
Newspaper Web sites kept a running count of the tabulations and the information zinged across the capital via text messages and urgent phone calls. During a reception at the Cuban Embassy in Mexico City, a woman shouldered into a group chatting near the refreshments table and breathlessly announced, "López Obrador is ahead by two points." Moments later, across the room, a man confided to a friend, "Calderón's ahead now."
Throughout Wednesday and Thursday, election supervisors in 300 vote-collection centers were poring over tally sheets from each polling place alongside representatives of each of Mexico's three major parties: Calderón's National Action Party, or PAN; López Obrador's Democratic Revolutionary Party, or PRD; and the Institutional Revolutionary Party, or PRI, whose candidate, Roberto Madrazo, has conceded.
The tabulating process was complicated -- and slowed down -- by a Mexican law that allows for the contents of the vote packets to be opened if the tally sheets, or the packages, appear to have been tampered with or damaged. Such packets are then sliced open and a vote-by-vote count is conducted.
This has enraged López Obrador and his supporters. They want a vote-by-vote count of every packet. But Luis Carlos Ugalde, head of Mexico's Federal Electoral Institute, said Wednesday that López Obrador's request is illegal and that opening all the packets would amount to a violation of Mexican law that would annul the results of not only the presidential race, but also thousands of other races, including contests for Mexico's legislature and a host of governships.
Outside Mexico's Federal Electoral Institute on Wednesday, dozens of demonstrators waved López Obrador signs and chanted: "This is fraud. He won."
