Maguindanao province under martial law (Jeoffrey Maitem/Getty Images)

On Nov. 23, 2009, 57 civilians were massacred in the Philippines by a group of more than 100 gunmen. At least 30 of the victims were journalists. Many were supporters and relatives of local political candidate Esmael Mangudadatu, including his wife, sister and aunt. Some were people who weren’t even part of the convoy but were in the wrong place at the wrong time. All were unarmed civilians. Reports describe mutilations before a government-owned backhoe dug a mass grave for the bodies.

The main suspect on trial for these killings pleaded not guilty today. He is Andal Ampatuan Jr., a mayor in Maguindanao province, and the murders were an act of election violence.

Politics is a bloody business in the Philippines. According to the New York Times, at least 126 people died in the 2007 elections and 189 people in 2004. (For a more in-depth look at Philippines election violence, take a look at a very informative PDF from the FES Philippines Office.) The FES paper notes that violence surrounding national elections has decreased, but local elections continue to spark injuries and deaths (along with property damage, kidnappings and coercion).

But why is it so violent? Partly because of a fierce rivalry between political families. These clans are powerful, wealthy and disinclined to give up their influence in the political sphere. (Check out a great blog post by Robert Mackey for more.) In their favor is the fact that some of these families have their own private armies, outfitted by the military with weapons to fight the rebellions and insurgencies that have troubled the country for so long. When a rival challenges someone from a family in power who has “gold, guns and goons,” things get very ugly very quickly.

Ampatuan is part of the Ampatuan clan, one of the powerful families in the Maguindanao province. His father had been governor of the province since 2001, but in 2009, he was challenged by Mangudadatu, member of another political family. Both families have strong ties to one another, but that didn’t prevent Mangudadatu from receiving death threats. He sent his female relatives to file his candidacy papers because it’s generally understood even in this violent region of the southern Philippines that you can’t harm women or children. Journalists accompanied them to witness the event.

Further complicating matters, the Ampatuans are closely connected to the Philippines’s president, Gloria Macagpal Arroyo. The government has been accused of giving Ampatuan and the other suspects special treatment.

Most accounts of the opening of Ampatuan’s trial mentioned that he spent the proceedings yawning.