For the current campaign, a spokesman for the Ecologist Green Party, Arturo Escobar, estimated that the party had received 150 million pesos, or about $10.7 million.

Corona said the five current planks of the Ecologist Green Party’s campaign platform were “designed perfectly” to help the much larger Institutional Revolutionary Party – the PRI in its Spanish initials, which ruled Mexico from 1929 to 2000 – appeal to a broader swath of voters.

The party calls for state vouchers for medicines, an end to fees for basic schooling, life prison terms for kidnappers, greater investment for water systems and – the only pledge related to the environment – regulation to make polluters pay reparations.

The presidential candidate who pollsters say is in the No. 2 position, leftist former Mexico City Mayor Andres Manuel Lopez Obrador, this week ridiculed the Greens’ call for state vouchers to obtain medicines at private drugstores.

“Do you know why the Greens are supporting Pena Nieto? Why they say they want to deliver free medicines? It’s because the owners of the Greens have franchises and are in the business of medicine,” Lopez Obrador said, speaking of the PRI’s candidate, Enrique Pena Nieto.

News reports say the extended Gonzalez family owns all or part of the El Fenix, Ahorro and Similares drugstore chains and Best pharmaceutical firm.

Escobar, the party spokesman, said the criticism “saddened” him because vouchers were “the most fair of all platforms under consideration by the Mexican people.”

“The medicine vouchers are aimed at guaranteeing that supplies of medicines in the federal social security system are sufficient and, if not, that voucher holders won’t have to wait,” Escobar said.

Currently, the Ecologist Green Party holds one Senate seat and seven seats in the lower house. But it holds significant sway in some states and municipalities, especially in Quintana Roo, the Caribbean state that surrounds Cancun, where it governs in alliance with the PRI.

Development near Cancun has uprooted mangroves to make way for hotels. A few environmental groups voice alarm and say the Greens are part of the problem.

“They remain quiet. And they are allied with the party that sells anything available in Quintana Roo,” said Guadalupe de la Rosa Villalba, head of Moce Yax Cuxtal, a nonprofit environmental group.

Some environmental groups temper criticism.

“We have to be objective. It’s not that they are all bad,” said Gustavo Alanis Ortega, the head of the Mexican Environmental Law Center, adding that some legislators had helped with laws on climate change.

Yet even though the Ecologist Greens are allied with the nation’s most powerful party, “the subject of the environment has been almost entirely absent from the campaign,” he added.

Sergio Aguayo, a political analyst and civic rights advocate, described the party as a “family business” that’s benefited from the environmental label.

The party, he said, “waves the very legitimate and well-known ‘green’ banner and takes advantage of the ignorance of a lot of people.”