MEXICO CITY -- A dramatic rupture in Mexico’s main opposition political party has aired the group’s dirty laundry and also could trip up President Enrique Peña Nieto’s ambitious agenda of reform.

The political fireworks riveted Mexicans on Monday, dominating airwaves and social media as leaders of the National Action Party, or PAN, bickered openly.

On one level, citizens were viewing another chapter in the agony of a party that ruled for the last 12 years but has been corroded by infighting and a bitter power struggle. Also at stake, potentially, was the ease with which Peña Nieto has been getting legislation through a fairly compliant Congress.

PAN chair Gustavo Madero over the weekend unceremoniously fired his party’s caucus leader in the Senate, Ernesto Cordero. Cordero will remain in the Senate, even continuing to hold his title of Senate president, but will no longer be the party’s go-to man.

Analysts quickly saw in this a slap at Mexico's former president, Felipe Calderon. Calderon’s conservative PAN held the presidency from 2000 until it lost the election last year, when Calderon’s term ended. He quickly decamped to Harvard University but remains close to Cordero and on the outs with Madero.

Cordero has been critical of Madero’s willingness to cooperate with Peña Nieto. On behalf of the PAN, Madero signed a so-called Pact for Mexico in which he pledged support for numerous initiatives that Peña Nieto and his Institutional Revolutionary Party, or PRI, are pushing.

The PAN has the second-largest faction in the Senate, and Peña Nieto needs its votes as he presses the reforms, which target the banking industry, telecommunications, the state oil monopoly and Mexico’s abysmal education system.

But Cordero of late has been resisting, and even joined forces with the left to put forward alternative legislation on campaign financing. That seemed to be the last straw for Madero, who dismissed Cordero in what he called the interest of party unity.

The party, clearly, is anything but united. Twenty-four of the PAN’s 38 senators are reportedly siding with Cordero against Madero.

“This is the most undemocratic behavior,” Cordero complained on a morning television talk show -- during which Madero phoned in to reaffirm his decision. Cordero accused Madero of being closer to the president's party than his own.

“The PAN cannot be a satellite of the PRI,” Cordero said at a later news conference.

The divisions within the PAN are heightened not just by disagreement over whether to cooperate with the PRI, but also by conflicting visions on the future and direction of the party, which lost badly in the 2012 election for president and several state governorships.

Fourteen states are holding local elections in July, and the PAN desperately needs to pull out victories to remain viable, analysts say.

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