Afghan watchers in the chancelleries of a dozen different states in South and West Asia know they are in for a long, tough weekend. Alongside them are spies, soldiers and business people, all keen for clues as to how the result of the presidential elections will affect the vast web of invisible regional networks that run through Kabul and South and West Asia, from the Levant to the Himalayas.

“Everybody always says each year is key in Afghanistan. But we are now in a period when everything is very much up in the air,” said one western official based in the region. The key local players are Pakistan and Iran, with India, China, the Gulf states, the “-stans” of Central Asia, and Russia playing lesser roles. Then there are informal “non-state” actors, extremist groups such as Al Qaeda, Lashkar-i-Taiba or the Pakistani Taliban, as well as criminal trafficking gangs who have a strong interest.

All protagonists are very conscious of the last time a superpower pulled out of Afghanistan after a decade or more of conflict. Following the Soviet withdrawal in 1989, India, Pakistan and Iran fought a bitter proxy war, each funding and arming local factions fighting for power in Kabul. The conflict had ethnic, religious and linguistic elements. Iran backed Shia and other minority groups who spoke Dari, which is closely related to Persian. The Taliban, composed of Pashto speakers from Afghanistan’s largest ethnic group, received support from Pakistan, the Gulf and informal regional networks of Islamic extremists.

Publicly, Afghanistan’s neighbours insist they want to avoid the anarchy of the early 1990s. Pakistan’s official position is that it “remains committed to supporting all efforts for a free and fair electoral process in Afghanistan ... as it would strengthen the prospects of stability”. This is challenged by Afghan officials, and some in Washington, who blame the tenacity of the insurgency, the failure of negotiations with the Taliban and a series of bloody attacks on their neighbours. There are fears that a win for Abdullah Abdullah, who played a key role in a faction sponsored by India in the 1990s, could prompt Pakistan to ramp up “interference”.

But Senator Mushahid Hussain of Pakistan said this would not happen. “Our main interest is in the process not the person. All candidates are part of the same system that spawned Mr Karzai post-9/11. It is not like they are coming from a different planet,” Hussain said.

Officials in India are watching Pakistan’s moves closely. Delhi has spent billions in Afghanistan since 2001 and has steered away from any security assistance that could provoke Islamabad. Salman Khurshid, the foreign minister, recently flew to Kandahar to open one project — an agricultural university set up in a former collective farm built by the Soviets and later used as a base by Osama bin Laden. Others involve power lines to Central Asia, a road to Iran which would break Afghanistan’s dependence on Pakistani ports, and a new parliament building.

Indian intelligence services have nonetheless made a significant effort to build up networks of contacts in strategic areas such as the south and south-west, one informed expert said. “Maybe someone would like to come to Delhi for medical treatment, or send a relative to an Indian university. That can be arranged. It’s just about making friends,” he explained.

Then there is Tehran, deeply involved in its neighbour Afghanistan, if only because of a perceived need to counter efforts of its great rival, Saudi Arabia, as well as Pakistan, to build influence there. Senior Iranian officials have recently visited India, with which Tehran has a warm relationship, rooted in Delhi’s need for cheap oil and mutual antipathy towards Pakistan and Kabul.

Mohammed Zarif, Iranian foreign minister, said in Delhi last month: “The occupation by foreign forces is inherently destabilising but if the vacuum is filled by the Taliban all of us will lose.” Iran’s cultural influence in the west of Afghanistan, supported by an aid effort, is immense.

Moscow, an active backer of anti-Taliban factions in the 1990s, has been less involved recently but China is increasingly prominent. Five years ago it was Afghanistan’s resources that interested Beijing. Now, it is also the security threat posed by radical Islamic groups and separatists from the Muslim southwest of China, of whom a handful have made their way to Afghanistan to train.

Chaos in Afghanistan would help narcotics smugglers but a breakdown in law and order might make opium cultivation more difficult, say analysts. The nightmare scenario of post-election political collapse would be an unequivocal boost for militant groups along the Afghan-Pakistani frontier, easing movement across the already porous border. Violence in Pakistan, and possibly in the disputed state of Jammu and Kashmir, would surge. There have been recent reports of militants who have fought and trained in Afghanistan in Syria and in Nepal, deserts and mountains more than 3,000 miles apart.

—By arrangement with the Guardian