Afghan refugees return from Pakistan at Spin Boldak after the border was reopened Oct. 19. (Qudratullah Razwan/EPA/Shutterstock)
To Pakistan, it's a fixed border. To Afghanistan, it's merely hypothetical.
It's the Durand Line: a legacy of the British Empire that's dividing the neighbors today.
For weeks, Pakistani and Afghan forces have fought across -- and over -- the frontier drawn by 19th-century Britain through historically Pashtun lands. Now, as they attempt to negotiate a lasting ceasefire, the Taliban-run Afghan government is increasingly challenging its legality.
Dozens of soldiers and civilians have been killed this month in skirmishes along the line. Pakistan launched airstrikes against cities across Afghanistan two weeks ago, an escalation that threatened to turn the border dispute into a wider war.
A temporary ceasefire since then has largely held. But ahead of talks in Istanbul this weekend, there was little optimism that Pakistan and Afghanistan would find common ground on the differences -- or the line -- that divide them.
What is the Durand Line?
British officials drew the 1,640-mile Durand Line in 1893 to demarcate the border between Afghanistan and what was then the British Raj after the empire won the second of the three Anglo-Afghan wars.
It was the waning days of the 19th-century Great Game, when Britain and Russia competed for control in Central Asia. London sought to make Afghanistan a buffer between its and Moscow's spheres of influence.
Under British pressure, Afghan Emir Abdur Rahman Khan accepted the loss of some ethnic Pashtun tribal lands, which were effectively annexed into British India.
The resulting frontier, which runs from China in the northeast to Iran in the southwest, was named for British diplomat Mortimer Durand, then the foreign secretary of India.
When Pakistan was created in the 1947 partition of India, it inherited the border. Since then, Islamabad has considered the matter settled, and has urged successive Afghan governments, and now the Taliban, to treat it as such. Ahead of the peace talks, Pakistani officials have reiterated that it's not up for negotiation.
But Afghanistan has long disputed the line's legitimacy. The Taliban have taken to referring to it as a "hypothetical" or "imaginary" border.
What's the cause of the recent tensions?
More vexing to Pakistani officials, the Afghan Taliban have shown little interest in securing it against militants or smugglers. Of particular concern to Islamabad are militants in Pakistan who have sworn allegiance to the Afghan Taliban and are waging an expanding insurgency in the territory effectively annexed by Britain more than 130 years ago.
Pakistani officials say the Afghan Taliban are actively supporting the militants' efforts to establish Taliban rule in border regions that were historically Afghan.
Pakistani officials blame most attacks on the Pakistani Taliban, or TTP. The group's leader, Noor Wali Mehsud, was the target of an alleged Pakistani airstrike in Kabul two weeks ago that ignited more than a week of border clashes. Mehsud survived the attack and has since reemerged on camera. (Pakistan has not claimed responsibility for the strike.)
The Afghan Taliban deny supporting the TTP and the TTP denies being supported or sheltered by the Afghan Taliban. A senior member of the group said talks between Afghanistan and Pakistan have had no effect on its operations.
"There is no pressure on our leadership from the Islamic Emirate to not fight in Pakistan,"
he said, using the Taliban regime's name for itself. He spoke on the condition of anonymity because he was not authorized to speak publicly.
How does the line affect the people who live there?
Support for the TTP in the tribal border region appears to be limited. But the militants have been able to make some inroads recently by capitalizing on the longtime perception among people on both sides of the border that the Durand Line was not supposed to have any effect on their everyday lives.
For much of the 20th century, members of Pashtun communities and other tribes crossed the border several times a day without being stopped by border guards. In the 1980s, Pakistani officials even encouraged this as they shepherded weapons and fighters over the border to support the Afghan mujahideen in their fight against the Soviet Union.
The mujahideen -- a precursor of the Taliban -- drew support and recruits from large ethnic Pashtun communities on both sides of the border.
"People didn't think of it as a border -- there were no passports, no visas,"
said Nisar Ali Khan Dawar, a 57-year-old tribal leader in Pakistan, who crossed the border freely into his 30s. “We went back and forth, attending weddings, funerals, or just to have dinner.”
What changed?
Free passage ended after the terrorist attacks of Sept. 11, 2001. The Taliban had sheltered al-Qaeda leader Osama bin Laden; the United States responded to the attacks by invading Afghanistan.
Under pressure from Washington, Pakistan closed border crossings and deployed troops to try to secure the border. Bin Laden slipped through to Pakistan anyway, but the impact on the border region has been severe and long-lasting.
Communities that depended on cross-border trade lost their revenue streams,” said Nisar Baaz, a local politician who supports closer Afghan-Pakistani ties. “People have been left with nothing,” he said.
After the TTP formed in 2007 and started launching attacks in Pakistan, Islamabad moved to fortify the Durand Line, eventually building a fence that now runs along most of its length.
Still, the border remains virtually impossible to surveil. TTP fighters and traffickers have frequently breached the fence, and some locals support the militants’ efforts.
“This unjust line has divided and weakened the Pashtun Afghans, and we will never accept it,”
Khan Dawar said.
Why are the Taliban pressing the issue now?
Analysts doubt that the Taliban government, recognized internationally only by Russia, can make a legal argument to challenge the Durand Line.
"Both Pakistan and Afghanistan have long treated the Durand Line as an actual international border,"
said Ahmer Bilal Soofi, a former Pakistani justice minister. He noted that Afghan officials, for example, collect customs payments at frontier checkpoints.
The Taliban might view tensions along the Durand Line as domestically advantageous. "By raising this issue again and again, they are using Afghan nationalism to distract people," said Zahid Hussain, a Pakistani political commentator.
"That may bring them short-term support at home,"
he said, "but it will only increase instability for both countries." Hussain cited the closure of Afghan-Pakistani border crossings for the past two weeks, which has left traders stuck on opposite sides of the border while millions of Afghans face severe hunger.
Shakir Afridi, a Pakistani trader inthe border region,saidthe financial losseshave cut deep.But even worse,he saidisthe effectonthousandsof expelledAfghan refugeeswho have been stuck onthe Pakistani sideofthe border,in limbo betweenthe country's pressuring them to leaveandthe country into which they're being forced back.
More than 1 million Afghans have been deported or pressured to leave by Pakistan since 2023,in what's been seen as an attempt to pressurethe Afghan Taliban into reining inthe TTP.
"Both sides should now at least allow the women and children to cross,"
Afridi said.