After failing to capture the presidency on two previous occasions, Andrés Manuel López Obrador shook up Mexico's leftist parties on Sunday by announcing that he will quit the coalition that supported his 2006 and 2012 bids.
Instead, López Obrador said that he was forming his own new faction, but added that he was leaving the Democratic Revolutionary Party (PRD), the Labor Party (PT) and the Citizens' Movement on friendly terms.
"In this new phase of my life, I am going to dedicate my imagination and work to the cause of transforming Mexico," said López Obrador, a former Mexico City mayor who lost the July 1 presidential race to Enrique Peña Nieto of the Institutional Revolutionary Party (PRI).
He will take over the reins of a movement that he founded some years ago, Morena, or Movement for National Regeneration, which is dedicated to social and political change. López Obrador said he would decide at a later date whether to formally constitute Morena as a political party and possibly take a third shot at the presidency in 2018.
A controversial figure, López Obrador made unsuccessfully attempts to challenge the results of the two past elections, alleging voter fraud and ballot stuffing. While he still refuses to recognize Peña Nieto's victory on July 1, even after the electoral tribunal had dismissed his claims of vote-buying, the PRD has decided to accept the ruling.
In the 2006 race, he narrowly lost to outgoing President Felipe Calderón of the National Action Party (PAN) by about one percent. This year, the PRI's Peña Nieto defeated him with 38 percent of the vote against López Obrador's 31 percent.
The leftist faction had accused Peña Nieto's PRI party of buying voters, even giving them bank debit cards loaded with cash in exchange for their ballots. The PRI has vehemently denied such claims.
Peña Nieto and the PRI, which is making a comeback after it was defeated in 2000 following a 70-year-old grip on power, will be installed in December.
PRD leader Jesús Zambrano said Monday he was confident of "a peaceful separation" because his party had been loyal to López Obrador during his second-place finishes in the last two presidential elections. But the split could mean that the left will have more than one candidate vying for the presidency in six years' time.