Why South Waziristan has long posed challenge to Pakistan's government
The traditionally restive region became a base for militants after the US ousted the Taliban in Afghanistan in 2001.
South Waziristan is a barren, mountainous region in Pakistan's tribal belt. It is home to several Pashtun tribes: principal among them is the Mehsud tribe, which has a reputation for courage and ferocity in battle.
The area was never fully absorbed into the British Empire during its long rule over India (and what is now Pakistan), though it formally acceded to Pakistan at the time of the country's creation in 1947.
A traditionally restive area that lies outside the government's official jurisdiction, the central government instead relies on so-called "political agents" to liase with tribal elders and to intervene in criminal, civil, and revenue disputes.
Following the United States' invasion of Afghanistan in 2001 and the subsequent early defeats of the Taliban, South Waziristan became a base for militants on the Pakistani side of the border to conduct operations into Afghanistan, as well as a hotbed of militancy aimed at Pakistan.
A sustained Taliban campaign over the past four years to behead hundreds of tribal elders â€“ termed the "political elite" by Hassan Abbas, research fellow at the Belfer Center at Harvard University â€“ in turn created a power vacuum that allowed the Taliban to tighten its grip on the area.