One of the most prominent elders in Tarin Kowt, Haji Mohammad Qasim, of the Popalzai tribe, tells Fairfax Media that Obaidullah preys sexually on young male students, dragging them off to parties in the Panjshir Valley, north of Kabul, and dumping them back at their Kabul dormitories in the early hours of the morning – with teeth marks on their necks.

Hilla Achekzai, an Oruzgani member of the Senate, accuses Obaidullah of murdering her husband and maiming her children. Obaidullah also stands accused of shielding Hakim Shujoyi, a murderous warlord who controls much of the Khas Oruzgan district in the east of Oruzgan province, from arrest and inevitable jail.

Both Qasim and Hilla accuse Obaidullah, an elder of the Barakzai tribe who also serves as an elected member of the national parliament, of treachery – of literally selling control of whole districts of their home province to the Taliban, in the hope that the insurgents might leave him alone. It sounds outlandish, but we turn up a book by a respected Afghan specialist, in which she writes of Obaidullah's outrageous deals with the Taliban while serving as a district governor.

It's a hornet's nest. But it warrants exploration to grasp an idea of the infighting that takes the place of governance and civil society as the tribes of Oruzgan engage in a near-constant battle for supremacy in which anything from calumny to murder, and occasionally the truth, is a legitimate weapon.

The objective is to wrong-foot a rival or an enemy, either with a direct hit or by lashing out, more judiciously, at a proxy. Success is measured by the extent of any damage to the target's reputation or, better still, denting or blocking a business deal or venture in which he or his tribe are engaged.

In the way of the Afghan tribes, Haji Mohammad Qasim inherited his assassinated father's job, as an advised to President Karzai – prestige and standing by entitlement, not merit.

Working either from the capital or from the family's imposing compound, set in riverside fruit and nut groves on the northern outskirts of Taren Kowt, the young man holds great sway in the complex affairs of the tribes – claiming that on his father's death he was "given the turban" of an elder in the dominant Popalzai tribe.

Qasim comes at the charges against Obaidullah obliquely, offering his own handling of the case as an example of how he works to protect the good name of the province. His objective, he explains, was to keep a sordid issue out of the parliament and out of the media.

The complaint by a group of students, about Obaidullah's exploitation of one student in particular, came to Qasim in his role as Karzai's adviser on tribal affairs. Instead of reporting it to the police, he put any formal response on hold and ordered that the students be locked down in their dormitory, to stop them going to the media.

He says he needed time to negotiate a deal between the students and Obaidullah, which he did – there was to be no official action on this particular complaint, but at a face-to-face meeting Obaidullah was made to give the students 1000 Afghanis [$AUD18.32] each. “Maybe they needed to buy socks,” says Qasim, who also gave the young men his solemn promise that if Obaidullah offended again he, Qasim, would strip him naked and take him before the TV cameras.

“Never happened,” says Obaidullah when he is confronted by Fairfax Media.

Qasim insists it was more important to protect the good name of Oruzgan than to address the individual rights of the student. But now, any need to protect the reputation of their home province counts for little as Qasim uses Obaidullah's conduct as the basis for an attack on all that is wrong with Afghanistan's fledging new system of governance, before he segues to a defence of the exercise of tribal power over this absurd import from the West – democracy.

Sipping tea from bone china cups, engraved with the words "your love is pure", Qasim quickly separates the real from the symbolic in the new Afghanistan – “the parliament is important, but it is the power of the tribes and the elders that protects us from enemies who try to control us.”

Skipping the unspeakable death and destruction of the mujahedeen wars of the early 1990s, when Afghan warlords like his late father, turned on each other, he explains: “For more than 30 years we've been fighting the communists and the Taliban – in my home there are eight war widows.

“Now they try to make the tribes fight each other [again] and elders who gave us good governance – like my father– have been assassinated. We're not as experienced as they were in dealing with conflict.”

This democracy thing is not working for Qasim. Dragging deeply on a Parliament brand cigarette, he lashes out at the parliament: “If we had good MPs, it wouldn't be a problem. They're always squabbling with officials, and demanding greater power and authority for themselves.

“In Oruzgan, our friends had noses and hands chopped off because they voted for these people, and here they are living the fancy life in Kabul. They're the ones who are corrupt, so thank God for tribal power because parliamentary political power is not working yet – the MPs mess up everything.

Focusing on Obaidullah as a symbol of all that is wrong with Afghanistan's parliamentary democracy, Qasim throws out his "gotcha!" charge: “If he's on an MP's salary of $2000 a month, how can he afford to get around Kabul in a $20,000 armoured car?”

Hajji Qasim takes time to explain how Obaidullah's treacherous deals with the Taliban worked: “He got money from the Taliban and a guarantee from the insurgents that there would be no future threats against him.” He then reveals that Obaidullah is able to get away with such conduct because he has tribal protection: “I could drag him in and demand to know why he does these things, but I'm Popalzai and he's Barakzai and his people would be offended and declare us as enemies.”

Hilla Achekzai, the woman senator, accuses Obaidullah of busily picking at the scabs of old sores, in the hope of provoking clashes between his tribe, the Barakzai, and the powerful Popalzai, that he believes can be manipulated to his advantage. Meanwhile, she says that she has actually observed others stashing arms for their own showdown with Hajji Obaidullah, who they accuse of complicity in two explosive murders – the assassination of Qasim's father JMK, and the shooting murder of Daoud Khan, who the Dutch had propped up as a rival to Popalzai hero and Oruzgan's provincial police chief, Matiullah Khan.

Hilla Achekzai denounces Obaidullah as "a killer and a traitor to his country", and the allegations pour out of her: “He was the local chief in Khas Oruzgan, but he sold the district to the Taliban and he destroyed my family – my two sons are disabled, I was wounded and my husband and father-in-law were killed. I'm a victim of his cruelty.

“He was supposed to be our district governor, our protection; but he was just like the Taliban – he orders his men to kill the tribal elders – 10 or 15 of them. After he sold us off to the Taliban, he was moved to Chora, and he did the same there – pretty well sold the people to the Taliban, again!”

On first telling, Achekzai's allegations fall into that "incredible" category. But later, we chance upon the aptly named Decoding the New Taliban, a collection by expert analysts, in which the former Dutch diplomat Martine Van Bijlert writes of such deals between district officials and the insurgency.

Writing about 2005-06, Van Bijlert reveals that such deals were common, with local strongmen allowing the Taliban to overrun their district as a ruse to reveal the weakness of local government and/or to press their case for reappointment.

Before visiting Obaidullah we are advised to look closely at his armed guards. Sure enough, some of them are very pretty and their eyes are etched with kohl… as they cradle their AK-47s.

He receives us in a small reception room at his Kabul home, where he sits on the floor, amid cascades of gaudily coloured artificial flowers, and all the while petting and stroking one of the smaller of 24 children he has fathered by his four wives.

Obaidullah admits to the expensive vehicle. But he insists it came as a gift from well-meaning businessmen, fellow members of the Barakzai tribe from the southern city of Kandahar, after the arrest of three would-be suicide bombers as they closed in on his Kabul home. “They got it from Dubai,” he offers, as he adjusts the coils of a turban that sits on his out-sized ears.

All this is petty, but it also is the stuff that causes wars and murder between the tribes, particularly in an environment in which the sense of tribal power based on numerical strength has been upended by the international community's overt backing for the Popalzai – which is only the fourth biggest of the tribes in Oruzgan. A further complication is that Karzai is of the Popalzai, which gives his tribesmen a huge leg-up in their local and national networking and standover tactics.

Such are the stakes that a good deal of the violence that often is presumed to be the work of the Taliban, is thought to be the work of tribal enemies – either acting alone or with the help of the Taliban. But observers tell us that some purported Taliban strikes simply would have been impossible without the complicity of the victim's tribal enemies.

“If it's open gunfire then, yes, it probably is the Taliban, but what about the rest?” a Taren Kowt local asks. “Assassinations, IEDs and that kind of stuff? There is so much tension between the tribes that they surely are responsible for some of these hits – alone or in league with the Taliban.”

This is the context in which we are assured that the Taliban could not have carried out the 2011 assassination of JMK, the most earth-shattering of the serial murders of Oruzgan's tribal leaders in the last decade, without the assistance of some of his tribal enemies.

“These things are co-ordinated; information exchanged. This is not merely my suspicion – it is very clear that the elders work with the Taliban. Think – this is just an extension of the whole idea that the Taliban can't do a thing unless it has help from the community,” the source explains.

A question gnawing at Oruzganis these days is the impact on the local power dynamic in the face of two key events next year – the withdrawal of foreign troops from Afghanistan and a constitutionally imposed end to the Karzai presidency.

When the foreigners go? “All power will revert to the tribal elders,” says the senator Hilla Achekzai. And an analyst who monitors events in Oruzgan warns of a possible collapse of the provincial government. “The three biggest tribes will be out for revenge on all of the Popalzai's heavy-handedness,” he says.

And when Karzai is gone? The young MP Raihana Azad leans in to address the implications of Karzai's departure: “[The West] has strengthened the warlord class so much economically that for the next decade or more they will be lords of the people. They are the new mafia. And with the financial and political capital they have, they don't need Hamid Karzai any more – they have their multiple villas in Kabul, they have tens of different businesses and they have millions of dollars in the bank.”

But for now, Karzai remains the hands-on President of the Islamic Republic of Afghanistan.

He's always been known to be a micro-manager, but an NGO staffer in Oruzgan still shakes his head when he tells of a phone conversation he could not have imagined.

In deference to intertribal sensitivities, he had invited equal numbers from the fiercely competitive Popalzai and Barakzai tribes to participate in a workshop on community empowerment.

However on the day of the workshop, absences meant that the Barakzai outnumbered Popalzai. The facilitator was getting down to business when one of the Popalzai participants produced a mobile phone and made a call. After a brief exchange in Pashto, he handed the phone to the NGO facilitator, saying: “It's for you.”

The facilitator heard a familiar voice: “It's Hamid Karzai here, and I'd like to know why you have more Barakzai than Popalzai in your workshop.”