To say that Ahmed Wali Karzai, the brother of Afghan President Hamid Karzai, was a controversial figure during his political career would an understatement. To those who dealt with him, and to some who lived under his control, he was anything but an ideal public servant. If you traveled around Afghanistan (particularly outside Kandahar), you would be hard pressed to find a single Afghan who had a genuinely positive view of the man, especially if you happened to be associated with an office in Kandahar Province that was attempting to establish a modicum of order based on the rule of law. Opponents of Ahmed Wali would often wake up the next day threatened by his many supporters throughout the province. And if you were a rival businessman who encroached on Wali’s territory or stole away a portion of his business clients, you would be lucky to escape injury or in some cases, death and disappearance.

Yet to the United States, Ahmed Wali was much more than a troublemaker or a business kingpin. Rather, he evolved into the most valuable source of information for NATO and proved to be a helpful partner in one of General David Petraeus’ most crucial counterinsurgency plans — the development of local anti-Taliban village forces. According to The Washington Post, Wali became such an important figure for the American counterinsurgency effort in Kandahar Province that American commanders found it necessary to travel with him, both to reinforce the general relationship between the two and to convince Afghan elders that the village defense force program was the best option to establish peace in their hometowns.

As is often the case when dealing with power brokers in Afghanistan, Ahmed Wali was not always the “indispensable” security ally that civilian and military officials on the ground painted him to be. It was only two and a half years ago when officials in the American embassy tried to remove him from his post as the chairman of the Kandahar Provincial Council, citing rumors that he was making millions off the foreign presence and millions more from involvement with the drug trade. Ambassador Karl Eikenberry had an especially difficult time dealing with the president’s younger brother who in some instances appeared to resemble more of a mafia chief than an elected provincial leader.

When it became apparent that commanders could not gather any hard proof of his involvement with corruption, the United States began to contain his power, then switched to working with him in a bid to provide basic security across the area under his control. Some credit Ahmed’s cooperation as a reason why the Taliban have been driven from their heartland over the past year. The Karzai brother was, after all, a stark opponent of the Taliban, not least because the insurgency challenged his authority but also because the Taliban presence weakened some of the links that filled his pockets and kept his patronage system going.

With Ahmed Wali gone, shot dead by a close confidant of the Karzai family, the provincial structure of Kandahar has been shaken to its core. Ahmed was an extraordinarily talented political manipulator, someone who managed to build partnerships with numerous tribes across the province while keeping his enemies off balance. His political acuteness was one of the reasons for the Central Intelligence Agency to allegedly reach out to him.

The focus now is on whether Shah Wali Karzai, Ahmed Wali’s brother, will have the ability to continue Ahmed’s vast power structure without being challenged from competing power bases. Washington, which had at least grown comfortable dealing with Ahmed Wali, will have to start its relationship with a Kandahar bigwig all over again. Whatever happens in the future, the death of Afghanistan’s most powerful leader in the south of the country — the same region that will witness a withdrawal of 30,000 American troops over the coming year — gives Afghans another reason to feel worried about their government’s capacity.