But at the same time, Mullen, in an interaction that followed his farewell address at the Carnegie Endowment for International Peace, acknowledged that he could understand Pakistan's insecurities vis-a-vis India and said he still believes that resolving the Kashmir imbroglio is the path to peace in the region.
When asked about Pakistan's perennial whining that the US has not provided the Pakistani military with attack helicopters that Islamabad has been clamouring for to take the fight to the terrorist networks, Mullen said he did not believe "there's a direct link between improving their helicopter fleet and the decision that the ISI has to make to strategically disengage."
"The ISI has been supporting proxies for an extended period of time. It is a strategy in the country and that strategic approach has to shift in the future," he maintained.
Arguing that the Haqqani network is one such proxy of the ISI, Mullen said, "There's absolutely no doubt in my mind that Haqqani was behind the recent attack on the American embassy in Kabul. The network was behind the truck bomb attack, which injured more than 77 US soldiers and killed five Afghans. And, you know, the Taliban have an atrocious record for killing Afghan citizens."
When a Pakistani journalist asked Mullen if it's worth for the US to fight a war in Afghanistan and lose young American lives in what has now become allegedly a battleground between India and Pakistan, Mullen agreed that "it's a fair question and we need to listen."
"We need to understand where Pakistan's interests lie, how Pakistan sees its future, and where certainly these shared interests combine," he said, and added, "We need to help each other achieve that."
He acknowledged that "this isn't just about Afghanistan and Pakistan. It's a regional issue and that includes India and other neighbours."
But Mullen reiterated, "Certainly in India -- and I know that has been for a significant period of time -- there's an existential threat with respect to Pakistan. It remains today and I've said a couple of years ago, and I believe today, solving Kashmir unlocks the whole place, that that's the path for long-term solutions," he argued.
Mullen conceded that it's a "very difficult issue that isn't going to go away, it isn't going to get better over time". "I have had these discussions, actually with both the Pakistani leadership as well as the Indian leadership."
On the recent assassination of former Afghanistan president Burhanuddin Rabbani and its impact to any reconciliation between the Taliban and the Afghan government since Rabbani was the key liaison in attempting to facilitate such a peace process, Mullen said, "It's really too soon to tell what the impact will be."
" Leaders need to respond deliberately here, ensure that this is not destabilising -- certainly from the standpoint of looking to the future," he said, but noted that "it does represent what is a very clear strategy on the part of the insurgents and the Taliban to try to assassinate as many leaders as possible."
But Mullen maintained, "It doesn't derail the strategy. Clearly, they are not winning in the field, if you will, and from their overall campaign, they've had a pretty difficult year. At the same time, the strategic effects here are not insignificant and we need to pay attention to it."