TORKHAM, Afghanistan » Some call them "the men who sit on golden chairs" — Afghan customs officials who preside over a vast ecosystem of bribery that stretches from dusty border crossings to the capital.

They have become fabulously wealthy by depriving their aid-dependent treasury of at least $500 million a year, according to the most conservative foreign estimates.

Unseating those kings of customs, or at least stemming their thievery, is now a job for President Ashraf Ghani Ahmadzai as he takes up his campaign promise of fighting graft. Customs is a central factor in rescuing the ailing economy, and accounted for 26 percent of government revenue last year.

Yet in interviews with a wide array of Afghan and foreign officials who live with the issue, a picture emerges of such rampant bribery and extortion that corruption can no longer be described as a cancer on the system: It is the system, they say. And it is deeply enmeshed with Afghan politics.

"The water is dirty from the source," said Khan Jan Alokozai, deputy chairman of the Afghanistan Chamber of Commerce and Industry, citing a Pashto proverb. "Governors and ministers, businessmen and bureaucrats — everyone is involved."

The scale of the problem is evident at Torkham, a major border crossing point on Afghanistan’s southeastern border with Pakistan. Every day, up to 500 trucks trundle across the Khyber Pass, kicking up clouds of dust as they cross into Afghanistan and enter a customs apparatus that has been transformed by a decade of foreign assistance.

The trucks pass a giant X-ray machine delivered by the U.S. military. Western-trained officials assess their cargos for import duties. The paperwork is entered into a computer system paid for by the World Bank. U.S.-financed surveillance cameras monitor the crossing.

Yet for Afghan officials, every truck represents a fresh opportunity for personal enrichment.

Border guards pocket a small fee for opening the gate, but that is just the start. Businessmen and customs officials collude to fake invoices and manipulate packing lists. Quantity, weight, contents, country of origin — almost every piece of information can be altered with the goal of slashing the customs bill, often by up to 70 percent.

"The only thing you can’t change is the color of the truck," said one customs official who agreed to meet after working hours to explain how the system worked.

The official, who spoke on the condition of anonymity because he feared losing his job, said he paid $5,000 to a customs administrator to secure his job, a low-level processing position, 10 years ago. It was a spectacularly good investment: He now makes up to $4,000 every month on top of his basic salary of $150. Similar positions now cost at least $15,000 and require political connections, he said.

Every official at the customs post in Torkham and nearby Jalalabad, where customs fees are paid, is complicit in the scheme, he said — even the office cleaners. A day earlier, for example, 85 trucks filled with garments had passed through customs, costing the importer $1,400 per truck in bribes: $900 to the customs chief, $250 to the customs broker, and $250 to be divided among various customs officials who facilitated the clearance.

The official said he had chosen to speak out partly out of guilt, and partly because he had been inspired by Ghani Ahmadzai’s election.

"This system is why I have clean clothes and good shoes," he said, pointing to himself. "But I know it is wrong and I want to stop it. This money belongs to the martyrs, the disabled and the widows. But if I raise my voice, I will lose my job."

At the customs headquarters in Jalalabad, the deputy director, Haji Baryali Gardi Wal, dismissed claims of corruption as "exaggerated," describing them as the calculated provocations of Pakistani, Iranian and Chinese intelligence agents.

"Afghanistan has many enemies," he said. "They want to embarrass us before the West to reduce the funds coming into our country."

In Kabul, the deputy finance minister for customs and revenue, Gul Maqsood Sabit, echoed that claim. "Ours is a world-class system," he said. "I admit there are problems. But we have come a long way."

It is certainly true that, partly thanks to at least $290 million in foreign training and equipment, the system has made strong progress in the past decade. Processing times at customs have fallen sharply – to two days from 10 at Kabul’s airport, and to 90 minutes from 18 hours at Torkham.

And revenue has soared to just more than $1 billion in 2012 from a paltry $50 million in 2003 — although it slumped last year because of uncertainty about the U.S. military drawdown.

Yet the system still loses more money than it gains. U.S. aid officials estimate that Afghanistan loses half of its customs revenue to corruption, the Office of the Special Inspector General for Afghanistan Reconstruction said in a report published last April.

One senior international official with long experience in customs reform said the figure was closer to two-thirds.

"For every dollar that should be collected, the trader saves 33 cents, 33 cents goes to the officials, and 33 cents to government coffers," the official said, speaking on the condition of anonymity under orders from his organization.

In conversation, Afghan officials casually reel out accounts of the ostentatious wealth enjoyed by senior bureaucrats and politicians involved with customs, usually involving expensive properties in Kabul, Dubai, Europe or Canada. Less prominent officials are also doing well. According to U.S. aid officials, some customs leaders are reluctant to visit Kabul for training because they would lose too much money in forgone bribes.

Ghani Ahmadzai, who vowed "strict legal action" against corruption officials in his Sept. 29 inauguration speech, is intimately familiar with the kleptocratic customs system — as minister of finance under President Hamid Karzai in 2004, he started the current modernization program. He will also be aware that previous attempts to clean it up have met with strong political resistance.

Under Karzai, criminal investigations into corrupt officials and businessmen were repeatedly frustrated through direct interventions from parliamentarians, ministers and even Karzai’s office, according to several Western and Afghan officials. Not a single senior customs official has been prosecuted for graft.

Other government departments viewed customs as a shakedown target, they said. Government auditors extort money from customs officials in return for a clean bill of health. Prosecutors accept cash payments to slow or derail corruption investigations.

If Ghani Ahmadzai is to truly attack this powerful web of interlocking interest, his main obstacle is political. A serious customs overhaul would hurt the interests of major tribal or regional power brokers with links to Ghani Ahmadzai or the country’s chief executive, Abdullah Abdullah.

The main border post in the north is controlled by Atta Muhammad Noor, the governor of Balkh province and a prominent supporter of Abdullah.

In the south, the powerful police chief of Kandahar, Gen. Abdul Raziq, has a tight grip on border posts at Spin Boldak, with Pakistan, and Nimroz, with Iran.

Aside from its sheer cost, endemic corruption is also a sign of pessimism among Afghanistan’s elites, whose hoarding of assets has been widely interpreted as a sign of worry as Western aid slows down and as Western combat troops pull out. Ghani Ahmadzai will seek to allay some of those fears by securing promises of continuing international aid at a donor conference due to take place in London late this month or early the next.

But he is also showing a steely hand on corruption. Just a few weeks into his tenure, he has already reinvigorated the stalled court investigation into the $900 million Kabul Bank fraud scandal. And he vowed to shake up the office of the attorney general, Mohammad Ishaq Aloko. "People must trust it," he said in a Twitter message posted on Oct. 8.

But with the political situation still fragile, some here worry that Ghani Ahmadzai may be moving too quickly.

"Corruption has become so interwoven with the political system in Afghanistan that it’s going to take years to undo," one U.S. official said. "And you can’t forget that Afghanistan is a treacherous place, where some actors are capable of anything."

© 2014 The New York Times Company