MANILA - President Arroyo moved swiftly to cut ties with a powerful Muslim clan whose son is blamed for massacring 57 people but experts say Philippine politics is infested with unholy alliances.
Political analysts describe the Southeast Asian nation of more than 7,000 islands as extremely corrupt where the central government is forced to team up with rogue politicians to win votes and have them control outlying areas.
Mrs. Arroyo's alliance with the family of Andal Ampatuan Sr., whose son and namesake has been charged with murder over the November 23 killings, is one of the most dramatic examples.
At least 9 Ampatuans are being investigated for their potential complicity in the massacre, including the father who has been the governor of Maguindanao province and an Arroyo ally for most of this decade.
The President's Lakas-Kampi-CMD coalition quickly expelled the Ampatuans from the party following the murders that allegedly took place to eliminate a rival's bid for governor.
But the Philippines' human rights commissioner, Lilia de Lima, pointed out the Ampatuans already had a well-known reputation as "warlords."
"(The clan) did not amass its cache of arms and assemble massive private armies overnight," de Lima said in a statement.
"These can only be done while national authorities impliedly condone the proliferation of arms among the political elite in the distant regions of the country."
Ampatuan's militia was tolerated for years because it helped the military hold at bay Muslim separatists who would have otherwise caused chaos there, said University of the Philippines political science professor Alex Magno.
"The occasional abuses committed by the warlords, until this week, were a small price to pay for the strategic role of keeping the Maguindanao area and those to the south free of insurgency," Magno told AFP.
The Muslim insurgency has claimed more than 150,000 lives since the 1970s, according to the military, so having allies in the south who can mitigate the threat is vital.
Interior Secretary Ronaldo Puno conceded that Mrs. Arroyo had to make a delicate balancing act as she dismantled the clan's armed militia, citing the threat of Moro Islamic Liberation Front guerrilla group.
"In forcefully addressing this crime we had to make sure we were not going to lose control of the area and of the armed people in the area," Puno said.
However powerful clan chiefs dominate across the mainly Roman Catholic nation -- ranked as the 41st most corrupt country in the world by graft watchdog Transparency International -- not just in the south.
Many have helped keep Mrs. Arroyo in power through two impeachment attempts and two military rebellions since 2001.
Among them is Luis Singson, an Arroyo aide who now holds the title of deputy national security adviser.
He rose to become the undisputed kingpin of Ilocos Sur province in the north after his uncle and local rival, Congressman Floro Crisologo, was assassinated by an unknown gunman in church in 1970.
Singson was a close ally of Arroyo's predecessor, Joseph Estrada, but switched sides.
Mrs. Arroyo embraced Singson and gave him criminal immunity when he testified in court that he accepted $2.7 million in tobacco excise taxes as well as nearly $6 million in kickbacks from illegal gambling operators to pass on to then president Estrada.
Amid the graft allegations, Estrada was toppled in a bloodless military coup in 2001 that allowed Mrs. Arroyo, then vice president, to assume the presidency.
She won a full 6-year term as president in the 2004 election, thanks in part to a huge batch of votes in Maguindanao province delivered by the Ampatuan clan.
Singson, meanwhile, has made headlines in recent months by admitting he beat up his estranged girlfriend and her new boyfriend.
Francisco Lara, of the London School of Economics' Crisis States Research Centre, said the weak central government ruled far-flung territories through an "elite bargain" in which regional power brokers got free rein in exchange for help in fighting state enemies.
The regional politicians got to control more than just the already lucrative formal economy, said Lara.
"The bigger prize is the power to monopolize or to extort money from those engaged in the lucrative businesses of illegal drugs, gambling, kidnap-for-ransom, gun-running, and smuggling, among others," he said.