While Osama bin Laden was escaping Afghanistan — Rumsfeld was in a meeting planning the Iraq war: book
President Bush flashes a "thumbs-up" after declaring the end of major combat in Iraq as he speaks aboard the aircraft carrier USS Abraham Lincoln off the California coast, in this May 1, 2003 file photo. Six months after he spoke on an aircraft carrier deck under a banner proclaiming "Mission Accomplished," President Bush disavowed any connection with the war message. Later, the White House changed its story and said there was a link.

The late former Defense Secretary Donald Rumsfeld is generally regarded to be one of the architects behind the war in Iraq even though Osama bin Laden, who was being given shelter in Afghanistan at the time, was the primary architect of the 9/11 attacks.

In a new biography by CNN reporter Peter Bergen about Osama bin Laden, it was revealed that Rumsfeld was ignoring what was happening on the ground in Afghanistan, allowing bin Laden to escape the country.

Bergen's new book The Rise and Fall of Osama bin Laden, he described the meetings Rumsfeld was taking while bin Laden was creeping over the Pakistan border from Tora Bora.

"It's on the border of Pakistan, the very porous border. So, you know, the fact is it's not an easy place to kind of cordon off," Bergen described in an interview with Fresh Air on Wednesday. "But the United States never tried. And to me, it's surprising."

Bergen describes the months following the attack on the Twin Towers as the best possible time to have located and either arrested or killed bin Laden. Instead, George W. Bush's administration took their feet off the gas.

"In the months after 9/11 the best chance the United States had to kill bin Laden was in the mountains of Tora Bora in eastern Afghanistan, where he and the core of al-Qaeda had retreated during mid-November," the book described. "He had been hiding there through most of the holy month of Ramadan."

"Bin Laden also knew that during the anti-Soviet jihad a relatively small group of Afghan holy warriors in Tora Bora had held off significant offensives involving thousands of Russian troops because its mountains and caves were easily defended," the book continues. "And he also understood that Tora Bora backed onto Pakistan's wild, ungoverned tribal regions, which was a perfect place for his followers to escape if this became necessary."

While some news reports claimed that bin Laden had stuffed the caves with weapons and ammunition, the reality is he had but one mortar and very little ammunition.

On Dec. 3, 2001 the bombing by the United States began.

"Not a second would pass without a fighter plane passing over our heads day and night," bin Laden recalled later, according to the book. "American forces were bombing us by smart bombs that weigh thousands of pounds and bombs that penetrate caves."

Bergen reported that between Dec. 4 and 7 the U.S. dropped 700,000 pounds of ordnance on Tora Bora where the notorious terrorist was hiding.

Speaking to NPR, Bergen described the World Trade Center pile of debris as "literally still smoking on December 12, 2001, which is the day that bin Laden escaped from Tora Bora." It was on that day that Secretary of Defense Donald Rumsfeld was being briefed about the future plans for the Iraq War by the Pentagon.

"And to me, that sort of speaks for itself," said Bergen. "Here is the architect of 9/11 escaping. And Donald Rumsfeld is getting briefed on the Iraq war plans. So, that shows you where their head was at. And there was plenty of information, well-known, at the time that bin Laden was at Tora Bora, but no will to get him. There were more journalists at the battle of Tora Bora by my count than there were American soldiers. There were about 100 journalists covering the battle and about 70 American soldiers in total."

During a news conference at the White House on March 13, 2002, former President W. Bush told reporters capturing bin Laden wasn't his focus.

"We haven't heard much from him. And I wouldn't necessarily say he's at the center of any command structure. And, again, I don't know where he is," Bush said. "I'll repeat what I said. I truly am not that concerned about him. I know he is on the run. I was concerned about him when he had taken over a country. I was concerned about the fact that he was basically running Afghanistan and calling the shots for the Taliban. But once we set out the policy and started executing the plan, he became -- we shoved him out more and more on the margins. He has no place to train his Al Qaeda killers anymore."

That was Bush's rationale for not focusing on going after the terrorist. When former President Barack Obama came into office, the situation changed and by May 1, 2011, when intelligence had information of bin Laden's whereabouts, the U.S. acted. He was ultimately killed in the raid on the compound in Abbottabad, Pakistan. People flocked to the White House chanting "USA! USA!" and celebrating the end of the U.S. foe as some semblance of justice for the thousands killed 10 years before.

Listen to the full interview with Peter Bergen below and his new book is on sale now.