An Indian village refuses to let women vote. An elected mayor is violently tossed out. Another village imposes a cruel and humiliating punishment on a woman accused of adultery.
In all three cases, community leaders have invoked traditions that many say violate democracy and human rights. In so doing, they have sparked a debate about whether Indian and rural communities must abandon some of their old rules, even as they win new respect and autonomy for their cultures.
The fear is that a long-awaited act of tolerance toward Mexico's 10 million Indians has also opened the door to intolerance.
Traditional law, known as "custom and usage," became a national issue after the Zapatista rebels' 1994 uprising in Chiapas. Congress approved limited recognition for traditional law, but the rebels demand full autonomy for the centuries-old system. That system -- communal labor, public punishment, voice votes and rule by assemblies -- "is what helps hold our community together," said Primo Aquino, 35, in the Zapotec village of Santa Ana del Valle.
But in parts of Mexico, it has meant rule by force and exclusion, machetes and machismo.
When Macedonia Blas, 46, was accused of adultery in July in San Ildefonso, an Otomi Indian village in Queretaro state, three women held her down and forced a burning chili paste into her genitals. What she did next was anything but traditional. She reported the crime to police. They brushed off the case as a minor offense, so last month she filed a complaint with a government human rights office.
Then she journeyed 230 miles to Mexico City to tell members of Congress about her ordeal. Speaking later to reporters, she described the experience as "very painful and terrible."
"For those women who think this is usage and custom, I don't want them to do this," Blas said in halting Spanish. "I don't want this to happen to other women."
Her supporters fear the case may give ammunition to foes of Indian autonomy. They contend the chili assault was an isolated act, not approved by the unwritten codes of traditional law. But the custom has been documented in several Indian communities.
Two suspects are on trial for the attack, but the charge -- causing injury -- could result in a mere 1,300-peso ($125) fine.
Those who support Blas say she was targeted not for adultery, but for leading development projects for women that challenged male supremacy in her village.
Bernardo Romero, head of the Queretaro State Human Rights Commission, and others are now debating how to stop such punishments without infringing on Indian autonomy.
"Some people may jump on this now to say, 'See, we told you they're savages,' " Romero said. "Many of these traditional practices are appropriate, but there are also some that demonstrate a lack of respect for women."
Guillermo Virafuentes, mayor of Huamuxtitlan in Guerrero state, faced a similar quandary Jan. 10 when he was called in to oversee elections in the Nahuatl Indian village of Santa Cruz. In Santa Cruz, tradition says, women can't vote. But this time, about 50 women protested outside the village hall.
"I asked them to let the women vote, to bring the village up to date with the times," he said. "The elders told me to show respect
They also asked him to get rid of two election observers, both female, he said. In the end, he gave in, telling the observers to leave and allowing the vote to proceed with only men present.
Like Virafuentes, Romero is in a tough spot. Sending in police "could be intrusive and cause more conflict," he said. But he is also pressing state police to prosecute the San Ildefonso "punishment" as an act of rape with an instrument.
Others, like historian Lorenzo Meyer, say even the most fervent defenders of traditional law should reject such practices. "Usage and custom must have limits," he said.
The clash between traditional and modern law has already cost lives. In January just south of Mexico City, one man was killed and several wounded when dissidents invoked traditional law to kick out the mayor, take over the town hall and declare autonomy.
Some aspects of traditional law are tough but effective, defenders say. Thieves can be forced to carry heavy stones or be put on public view in primitive jail cells -- deterrents that rely more on shame and ostracism.
But voting by a show of hands discourages dissent. Some communities will absolve a rapist who offers to marry his victim. A few even allow women to be sold into informal marriage.
It won't be easy to change customs that evolved over centuries. "Intervention is the easy way, but in the end it will lead to conflict," said Oscar Banda, leader of the Yax Kin Indian support group. "The important thing is to get the community discussing it, and let them reach a consensus on how to change these practices."
In Santa Ana in Oaxaca state, councilmen walk the streets carrying polished wooden sticks, symbols of authority never entrusted to a woman. But the village is hardly stuck in the past.
Santa Ana voted over the last year to ease communal work quotas, hold video conferences with absentee villagers, and build an environmentally friendly water treatment plant.
"We're trying to modernize, bring things up to date," said Deputy Mayor Ramon Bautista Sanchez, 72. "There are things that made sense in the past, in our grandfathers' time, but which are now obsolete."