2011 was a disastrous year for US-Pakistan relations. The BBC looks back with a guide to the year's major flashpoints.
The year got off on a terrible footing when a US citizen, Raymond Davis, shot dead two Pakistanis at a road junction in Lahore. A car that came as back-up for him also hit and killed a motorcyclist.
Initially, American officials appeared vague on details of exactly what Mr Davis was doing in the country, though it was later revealed that he was a CIA contractor.
Washington insisted he had diplomatic immunity but there was a huge clamour from the Pakistani public that he be tried in a criminal court here.
After several weeks, Mr Davis was released and returned to the United States. The victims' families accepted American compensation but there was outrage across Pakistan.
At anti-American demonstrations, effigies of Mr Davis were burned and the Pakistani government was also ridiculed over its perceived weakness.
"The Raymond Davis case showed the Pakistani state to be powerless in front of the Americans and it hurt national pride," says the political analyst Pervez Hoodbhoy.
"There really was an element of injustice but it was just one step down the slippery slope of 2011."
On 17 March, just a day after Mr Davis was released, the CIA conducted one of its deadliest ever drone attacks in Pakistan.
Missiles from a remote-controlled US aircraft struck a tribal gathering in North Waziristan. The final death toll was estimated to be well over 40; locals said most of the dead were civilians.
In an unusually strong public statement Pakistan's army chief Gen Ashfaq Kayani, talked of it being "highly regrettable that a meeting of peaceful citizens including elders of the area was carelessly and callously targeted with complete disregard to human life".
The proportion of civilian deaths in years of drone strikes is difficult to verify. But for many here it is unpalatable that a foreign country carries out attacks on Pakistani soil.
Behind the scenes, Pakistan's civilian and military leaders are thought to have given their support to the policy until recently - though they have never said so publicly.
At the end of 2011, the mood appears to have changed. Gen Kayani ordered that any drones be shot down and the Americans were ordered to vacate the Shamsi Air Base in Pakistan.
The drama in Abbottabad at the beginning of May is likely to have had a lot to do with that shift.
It was with a sense of shock that Pakistan greeted the news in May that Osama Bin Laden had been found and killed in a US raid in the Pakistani garrison town of Abbottabad, a short distance from the country's foremost military academy.
When the world heard that he could have been living there for more than five years, many suspected Pakistani collusion.
Some in Washington demanded an end to the large amounts of American aid that came to Pakistan.
"It had the most devastating impact on Pakistan's international standing," says Simbal Khan of Islamabad's Institute for Strategic Studies.
"This one incident of OBL has sadly somehow brushed aside the whole 10-year record of Pakistan fighting along[side] the international community against al-Qaeda."
The Bin Laden compound is still standing. But after those few days, in which it was nothing less than a tourist attraction, it remains sealed off.
However, to this day many Pakistanis still say they do not believe he was ever there or that he was killed.
It could be one explanation for why there was surprisingly little public soul-searching in Pakistan about what led to the al-Qaeda leader's presence in Abbottabad.
Instead, furious debate has surrounded the American raid and how it was carried out without Pakistani permission.
Islamabad and Washington appeared to have just about brought their relationship back from the brink when tensions suddenly sky-rocketed again in September.
There was a truck bombing in the Afghan capital, Kabul, followed a few days later by a prolonged attack on the US embassy there.
The Haqqani wing of the Taliban said they were responsible. America's most senior military officer, Adm Mike Mullen, unequivocally blamed Pakistan.
"The Haqqani Network... acts as a veritable arm of Pakistan's Inter-Services Intelligence (ISI) agency," the chairman of the Joint Chiefs of Staff told a US Senate panel, days before leaving office.
"With ISI support, Haqqani operatives planned and conducted that truck bomb attack, as well as the assault on our embassy."
His open accusations of the "double game" being played by the Pakistanis stunned the establishment here.
"On one hand there has been the infiltration of religious right-wing thought into the Pakistani ranks," Professor Hoodbhoy.
"On the other hand there has been a pragmatism within the army, which says we cannot afford to break ties with the Americans, hence this duplicity."
"For years Pakistan has run with the hares and hunted with the hounds. But that's no longer possible."
2011 ended with another serious blow to relations. 24 Pakistani soldiers were killed in a Nato bombing raid on a border post.
It led to Pakistan blocking supply routes to coalition forces in Afghanistan and to Pakistan's boycott of the Bonn conference on the future of Afghanistan.
Washington has talked of "regret" but has yet to offer an apology, to the anger of many here. It has, however, acknowledged that there were mistakes made by Nato troops.
"The Pakistani public will not be satisfied unless heads roll over this," says the Institute of Strategic Studies' Simbal Khan.
"What comes across from this incident is the lack of trust that has been bedevilling this relationship.
"Both sides are unhappy with the downward spiral and there is no option but to redraw the lines of engagement."
Professor Hoodbhoy thinks things have gone beyond the point where that is possible. "The US has made huge misjudgements during 2011," he says.
"And while the Pakistani military leadership doesn't want a rupture with United States because of our huge economic dependence on them, there is the pressure within the ranks.
"They have seen Pakistan humiliated in the Nato attack, humiliated at the time of OBL and at the time of Raymond Davis."
"The generals see the rising Islamic radicalism creeping within the ranks and they know if they don't stand up to the Americans, they have no future," says Professor Hoodbhoy.
"I think relations between Pakistan and US have deteriorated to a point where I think the break is not too far away."