Even as Pakistan's ambassador to the United States, Husain Haqqani was one of the most eloquent critics of Pakistan's military, the nuclear-armed country's most powerful institution.

Haqqani, once derided at home as Washington's ambassador to Pakistan for his pro-Western views, has taken a step further, accusing the government of directly supporting militant groups in his latest book "Magnificent Delusions".

Now a professor of international relations at Boston University, he was ambassador to the United States from 2008 to 2011, a turbulent time in US-Pakistan relations that culminated in a raid by US special forces in May 2011 that killed Al-Qaeda leader Osama bin Laden.

Haqqani resigned in November 2011 and left Pakistan after becoming involved in a scandal surrounding a secret memo that accused the army of plotting a coup and sought help from the United States to rein in the military.

Haqqani, who has denied any connection to the memo, spoke to Reuters by telephone from the United States about his book and his views on US-Pakistan relations.

Q: Why do you believe Pakistan supports militant groups?

A: As far as terrorism is concerned, Pakistan was the conduit of weapons and training for the jihad in Afghanistan against the Soviets. After that, Pakistan switched it to India, especially in Kashmir. And that is the point at which the United States said "You are engaging in terrorism". The Pakistani response was "But we started it together".

The problem is that the pro-jihadi narrative has become so mainstream that it is very difficult for any government to ... put all jihadis out of business. But Pakistan would not find peace without putting all jihadis out of business.

Q: Why is this happening now?

A: The whole idea of building a nation around religious nationalism has backfired. What has happened is that religious nationalism has only produced extremism. If Pakistan were to be an Islamic state, the question arises "What kind of Islamic state?" We are now in a virtual civil war between various sects and militias attached to these sects who don't tolerate each other.

Q: Pakistani Prime Minister Nawaz Sharif just concluded talks with President Barack Obama during his visit to the United States. What do you think they really talked about behind closed doors?

A: There is a Groundhog Day quality to Pakistan-American discussions, especially since the end of the anti-Soviet war in Afghanistan. Each time there is a change in government in Pakistan or in the United States there is a build-up of hope that maybe this time we will resolve it.

That is why I titled my book "Magnificent Delusions". Everybody is just deluding himself. The big American delusion is that America gets leverage with Pakistan by giving it military and economic aid. It doesn't.

It just improves its access but it does not give it leverage because the Pakistani establishment does what it thinks is in Pakistani interests. They do not allow an honest debate about what is in Pakistan's national interest. They do not allow people like me to argue that our policies are not in our national interest.

On the other hand, the Pakistani delusion is that Pakistan is going to succeed with the kind of policy it pursues. In fact, what America needs to do is prove to Pakistan that its policies will fail instead of buying time with a little bit of aid.

Q: What do you expect to happen now that US forces are leaving Afghanistan and Washington's focus shifts to other parts of the world such as Syria?

A: Pakistan needs to think and plan for the day when America will lose interest in Pakistan and the region. Pakistan's best options ... are to find peace with its neighbors and have ambitions that are realistic, not delusional...

If Pakistan is able to switch this focus from jihad to economic development ... then perhaps even an American abandonment will not be such a big problem for Pakistan.