In his latest book "Playing to the Edge", Michael Hayden, the former CIA director used the word "duplicitous" for the ISI and its then head Ahmed Shuja Pasha when he was asked by The Time magazine to draft a short write up on the ISI chiefs.
The Time magazine in 2011 named Pasha as one of the world's 100 most influential people.
"I agreed and then called current and former US government officials to get some advice on what to say, particularly something to say that might help the overall relationship," Hayden wrote.
"I asked for specific words to describe Pasha and the ISI. One of the gentler ones suggested to me was 'duplicitous'," the former CIA chief said adding that this wasn't particularly useful.
"So I just observed that "changes in Pakistan— the growth of fundamentalism, nationalism and anti-Americanism have squeezed the space in which any ISI chief can cooperate with the US," he wrote.
Pasha, a Pakistani patriot and American partner, now must find these two roles even more difficult to reconcile and at a time when much of US counter-terrorism success depends on exactly that," Hayden wrote in the book that hit the stores on Tuesday.
Hayden who was also the director of national security agency wrote that some uninformed observers have opined that the Abbottabad raid in May 2011 to kill Al-Qaeda chief Osama bin Laden poisoned the relationship between the US and Pakistan.
"It didn't. It merely tore the veil off," he wrote.
The famous statement of the then chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, that Haqqani network was a "veritable arm" of the ISI was an expression of his frustration.
Reflecting on the increasing frustration in the previous Bush administration, Hayden said he remembers an incident during one of the daily presidential briefing on Pakistan, George W Bush, he just yelled to the outer office.
"Get me Musharraf!". Years after he left the government, Hayden said as he reviewed his Thursday morning briefing scripts for the president and was struck by how much they focused on terrorism, and within terrorism how much they were about South Asia— Pakistan and Afghanistan.
"And during the last six months of the administration, I was struck that we covered the hunt for HVT-1 (High-Value-Target-1, ie, bin Laden) and HVT-2 (Ayman al-Zawahiri) in practically every session. We were certainly focused," he wrote.
Pakistan, he said, was one area where all the dilemmas of the war on terror seemed to play out in their most extreme form. The CIA had actually good success working with Pakistani ISI sweeping up al-Qaeda in the settled regions of that country.
Hayden said professional-level CIA exchanges with Pakistan's ISI were usually dispassionate and factual. Mid-level ISI officers seemed to get it in terms of what the US was doing and why, he said.
"But the ISI often acted like a plural noun and there were occasional issues, like their trying to squeeze the manpower that the CIA could get into the country," he added.
The US was clearly getting some very good intelligence there, a reality that must have made the ISI incredibly uncomfortable, he said.
"They may or may not have had a clear window into how we were developing intelligence, but they correctly judged that it would be harder to do if we had fewer people in the area. So the ISI began to quibble, question, delay, and ultimately deny visa requests for multiple officers we were trying to dispatch," Hayden wrote.
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