MEXICO CITY -- One of President Enrique Peña Nieto's signature efforts to shake up the country -- a broad plan to overhaul the education system -- has run into violent protests that underscore how difficult it may be to carry out, particularly in some volatile states with poor academic performance.
Armed with iron rods and rocks, dozens of masked members of the teachers' union in Guerrero State attacked the local offices of the four major political parties on Wednesday, smashing windows and overturning furniture. They also set fire to the office of the Institutional Revolutionary Party, or PRI, to which Mr. Peña Nieto belongs.
On Thursday, in a further sign of the growing conflict over education changes, teachers marched down Mexico City's main boulevard, temporarily closing it down.
The education overhaul, which transfers power from the potent teachers' union to the federal government, proposes periodic teacher evaluations to determine appointments, salaries and dismissals -- a major adjustment for workers who are accustomed to buying or inheriting their positions and who have had, until now, virtual immunity from the state.
The president's plan, signed into law in February, and the subsequent arrest of the seemingly untouchable boss of the teachers' union, Elba Esther Gordillo, were seen as political victories for Mr. Peña Nieto, whose agenda is focused on retooling the country's education, labor, energy and telecommunication sectors.
But additional legislation is needed to carry out the new education law, and dissenting teachers are trying to influence it through a mix of paralyzing protests and vandalism in parts of the country.
"They won't stop it," said Eduardo Andere, an education expert at ITAM university. But growing pressure could push legislators to give secondary legislation "language that permits more local meddling," he said.
Other obstacles loom. A "pact for Mexico" that Mr. Peña Nieto reached with opposition parties on a range of issues is in danger, after rivals erupted over a recording in which PRI officials in one state were heard discussing how to use antipoverty programs to buy votes in coming local elections.
Mollifying the local offshoots of the teachers' union was never going to be easy, as they historically have mobilized against any perceived threat to their power.
The states of Guerrero, Oaxaca and Michoacán, among the poorest in the country and with the lowest academic performance, have a particularly long history of mass unrest.
"There isn't a governor who can get them in line," said Sergio Cárdenas, an expert on education at CIDE, a Mexico City research institute. "And they are capable of enormous mobilizations."
In Oaxaca, the site of violent strife set off by teachers' protests in 2006, members of the teachers' union blocked streets and entrances to shopping malls this month, bringing parts of the state capital to a virtual halt.
This week, protesters in Michoacán held up eight buses and kidnapped the drivers; took temporary control of two fuel trucks belonging to the national oil company; and declared an indefinite strike that is likely to affect thousands of students.
And in Guerrero, where civilian groups have taken up arms amid a wave of organized crime-related violence in recent months, members of the teachers' union have closed down the highway connecting the tourist port of Acapulco to Mexico City on several occasions. Protesters also attacked the state congress with rocks and eggs.
Few arrests have been made in connection with the protests, which may be slipping out of union leaders' hands.
"There are several actions that even we, of the negotiating commission, do not know about," Minervino Morán, a spokesman for the protesters, said during an interview with Milenio Television.
This article originally appeared in The New York Times.