NEW YORK — Back in November 2001, just a week after Kabul fell to the U.S.-led invasion forces in Afghanistan and just as the city of Kunduz began to capitulate, the air filled with the steady drone of C-130 transport aircraft landing at the dusty airstrip.

The planes, American-built but flown by the Pakistani Air Force, ostensibly arrived to pick up a few dozen diplomats and their families ahead of the final onslaught on the city. In fact, the transports were stuffed full of agents of Pakistan’s Inter-Services Intelligence (ISI), along with as many as 4,000 Taliban leaders and foot-soldiers.

It was an outrage I wrote about at the time, but amid the rubble of 9/11, most people shrugged it off. Now, in the wake of this week’s revelations about the extent of continued ISI contacts with the Taliban, you have to wonder how many of those who flew out of Kunduz courtesy of the ISI (and with the tacit permission of the George W. Bush administration, since we controlled the skies) have filtered back to kill American soldiers.

The leaking of a small library of classified documents on the Afghan War should put an end to this lie once and for all. Among the revelations found in the documents is that ISI agents meet regularly with Afghan Taliban commanders to help plot attacks and assassinations of selected Afghan officials.

Not all of this may be true, of course — if the last decade has taught us anything it’s that intelligence is rarely all that intelligent. But the fact that Washington tried hard to prevent this information from coming to light speaks volumes, as does the fact the writers of these leaked reports clearly understand that a debate rages within U.S. and NATO circles about how best to confront Pakistan’s duplicity.

A cable filed about a Taliban meeting at which plans for an attack on NATO troops was discussed, noted the fact that Hamid Gul, the highly visible former ISI director, was in attendance. A comment inserted into the field report warned against undue assumptions.

"Hamid Gul was director general of ISI from 1989-1989 and, according to ISI, has not been an official with ISI since that time. It was not known whether Hamid Gul was acting with the knowledge or consent of ISI, or whether any portions of ISI were aware of his activities," a section of the report read.

Substitute, say, “George Tenet” for “Hamid Gul” and ask yourself whether the CIA would have known he was there.

Another hint: Several of the cables end with this ominous note: “This information MUST NOT be disseminated to the GoA” — the government of Afghanistan, or other ostensible “allies.”

Deeply ensconced in Afghanistan ever since the anti-Soviet guerrilla war of the late 1970s, Pakistan’s ISI cultivated, trained and armed the Taliban, helping it oust Afghanistan’s post-jihadist government and, ultimately, to ensure the maniacally fundamentalist faction it backed held sway over most of the country. Its expertise was honed by CIA agents during the anti-Soviet jihad and fueled by Saudi money (and, inevitably, Saudi Wahhabist ideology, too).

When the United States wrote Afghanistan off following the Soviet withdrawal, the Pakistanis took a longer-term view. They live next door, after all, and live on a constant and paranoid war footing against their historic rival, India.

Ties forged on the battlefields of the 1970s turned to lasting relationships, and those ties remain to this day – publicly denied by Pakistan, of course, but no one who has been in the region for any period of time can fail to appreciate the extent to which Pakistan values its “sources” to the north.

The United States, which decided in 2001 it could not win in Afghanistan without Pakistan’s help, has willfully disregarded this relationship — and the terrible price our own troops have paid as a result — all these years. The ISI, indisputably, has received billions of dollars from the $9 billion sent to Pakistan since Sept. 11.

When the Obama administration took office, new rules took effect that prevent some of the worst abuses — for instance, the redirecting of that aid to buy weapons meant for a war with India rather than the insurgency in northern Pakistan. Still, as part of his own commitment to win in Afghanistan, Obama also approved $7.5 billion more to be distributed by 2014. And to anyone who thinks Congress’ demands for a transparent accounting of how it’s spent will be met, I have a bridge to sell you.

The ISI, like some elements of Pakistan’s military and important factions of Pakistani society more generally, view the establishment of a relatively modern, pro-Western Afghanistan as a strategic threat. To Pakistan, Afghanistan provides “strategic depth” against the possibility of war with India — a mountainous hinterland to retreat to in case the deluge of India’s military ever strikes — like Hitler’s fanciful “Bavarian redoubt” in the final days of World War II.

In fact, Pakistanis and Indians fight regularly in Afghanistan via the two intelligence agencies — the ISI and India’s External Intelligence Agency — which run operations against each other and spread money and weaponry around to win allies. India, which accused the ISI of training the terrorists who struck in Mumbai in 2008, also believe ISI operatives aided two deadly attacks on its Kabul embassy in recent years.

Allegations over the years that the ISI also aided and abetted al-Qaeda still look thin, but certainly Pakistan did nothing to pressure the Taliban to bring Osama bin Laden to account after the murderous attacks in Kenya and Tanzania in 1998, nor when the USS Cole was nearly sunk in Yemen two years later.

The Bush administration used the usual Washington bullshit to obscure what had happened. Only a month and a half earlier — in late September 2001 — the United States had informed Pakistan that it had either cooperate in the war of vengeance against Al Qaeda about to begin, or face the consequences of the United States turning to its ally India, who had quickly offered its territory in support after the 9/11 attacks.

That Indian offer looked like a tactic to military planners at the time — India is notably prickly about doing anything to prolong the influence of western powers in its backyard. In any case, running a war in Afghanistan from Indian territory probably wasn’t feasible.

Yet the extent of the compromises American policymakers have had to make to run one with the tacit assistance of Pakistan now loom very large indeed. Pakistan’s inability to control its own territory and prevent it from being used as a safe haven was challenge enough.

There can be little doubt now that the Pakistani intelligence service has actively conspired to defeat the U.S.-led campaign in Afghanistan. The extent to which Washington has gone to help abet the myth of Pakistani commitment to a new, stable Afghan order looks a lot like self-delusion.