The planning for 9/11 was done in Pakistan, not Afghanistan, it now transpires.

Here’s the report that reveals the facts of the matter:

A trial under way in Chicago could be the next nail in the coffin of Washington’s unholy alliance with Islamabad, which looks more like a state sponsor of terror.

The federal case involves terror suspect David Headley, a Pakistani-American who says he was recruited by Pakistani intelligence (known as the ISI) to help attack India’s business hub.

In graphic testimony, he has revealed ISI’s role in the murder of 163 people — including six Americans — in the Mumbai terror attack of 2008.

Headley, who pleaded guilty last year to casing targets in Mumbai and European cities, detailed meetings he had with the Pakistani military and ISI officials. He’s fingered a Pakistani intelligence officer, a former Pakistani army major and a navy frogman among key players behind the Mumbai massacre. He’s also testified that ISI hooked him up with al-Qaida in Pakistan.

FBI agents and U.S. attorneys prosecuting the case find him credible. Among corroborating evidence: emails between him and his ISI handlers.

Headley swears that Mumbai was “ISI jihad.” But there may have been another ISI jihad — 9/11. Scattered throughout the 9/11 Commission Report is overwhelming evidence the 9/11 operation was rehearsed in Pakistani safe houses and financed through Pakistani money-transfer networks.

“Almost all the 9/11 attackers traveled the north-south nexus of Kandahar-Quetta-Karachi,” the report said. In fact, the hijackers met with Khalid Sheikh Mohammed in Karachi, where the 9/11 mastermind instructed them on Western culture and travel.

He showed them movies depicting hijackings. He passed out brochures for flight schools, and phone directories for San Diego and other U.S. cities. He used game software to increase their familiarity of jetliner models and functions, and advised watching the cockpit door during takeoff and landing.

“To house his students,” the report said, “KSM (Khalid Sheikh Mohammed) rented a safe house in Karachi with money provided by (Osama) bin Laden.” KSM and other key plotters — including Ramzi Binalshibh and Mustafa al-Hawsawi — found refuge in Pakistani cities after the Twin Tower/Pentagon slaughter. Residual funds for the operation were wired back to Pakistan.

In short, the 9/11 plot was hatched in Pakistan. So it only follows that the man who gave the final order to attack us on 9/11 — bin Laden — was found hiding not far from Islamabad, right under the nose of the Pakistani military.

The 9/11 Commission concluded that the ISI introduced bin Laden to Taliban leaders in Afghanistan. Then, years later, they warned him U.S. missiles were heading his way. The rockets missed bin Laden, but killed ISI personnel. What were they doing there? Training jihadists at bin Laden’s camps to fight as proxies against India in the war over Kashmir.

The panel found that al-Qaida terrorists have been marshaling war against the U.S. from inside Pakistan since 1993.

On Jan. 25, 1993, Mir Amal Kansi, a terrorist from Pakistan, shot and killed two CIA employees at Langley. Kansi returned to a hero’s welcome in Pakistan. Only a month afterward came the World Trade Center bombing, which was hatched by Ramzi Yousef, who fled back to Karachi where he and his uncle KSM went back to the drawing board.

After 9/11, U.S. intelligence found KSM living in a villa in Rawalpindi — headquarters of the Pakistani army.

In preparing the 9/11 attack, al-Qaida enjoyed “the operational space” within Pakistan’s cities to gather and sift recruits and to indoctrinate them, according to the 9/11 report, which was published in 2003.

“It built up logistical networks running through Pakistan,” it said. “Within Pakistan’s borders are 150 million Muslims, scores of al-Qaida terrorists, many Taliban fighters and — perhaps — Osama bin Laden,” the report added.

How right it was. Bin Laden’s deputies are more than likely holed up there as well. We’ll find them — if the CIA and Special Forces are allowed to keep up the hunt.

Can this possibly mean that the war in Afghanistan, now obviously pointless, was never necessary?

And is American tax-payers’ money, given to Pakistan to buy its alliance, used there to train terrorists to attack America?

Seems so.