ISLAMABAD -- You know a friendship has gone sour when you start making mean jokes about your friend in front of his most bitter nemesis.
So it was a bad sign last week when the U.S. Defense Secretary Leon Panetta joshed in front of an audience of Indians about how Washington kept Pakistan in the dark about the raid that killed al-Qaida leader Osama bin Laden a year ago.
"They didn't know about our operation. That was the whole idea," Panetta said with a chuckle at a Q&A session after a speech in New Delhi, raising laughs from the audience. The bin Laden raid by U.S. commandos in a Pakistani town infuriated Islamabad because it had no advance notice, and it was seen by Pakistan's powerful military as a humiliation.
The U.S. and Pakistan are starting to look more like enemies than allies, threatening the U.S. fight against Taliban and al-Qaida militants based in the country and efforts to stabilize neighboring Afghanistan before American troops withdraw.
Long plagued by frustration and mistrust, the relationship has plunged to its lowest level since the 9/11 attacks forced the countries into a tight but awkward embrace over a decade ago. The United States has lost its patience with Pakistan and taken the gloves off to make its anger clear.
"It has taken on attributes and characteristics now of a near adversarial relationship, even though neither side wants it to be that way," said Maleeha Lodhi, who was serving as Pakistan's ambassador to the U.S. on Sept. 11, 2001, and was key in hurriedly assembling the two countries' alliance after the terror attacks.
The latest irritant is Pakistan's refusal to end its six-month blockade of NATO troop supplies meant for Afghanistan. Even if that issue is resolved, however, the relationship may be on an irreversible downward slide. The main source of U.S. anger is Pakistan's unwillingness to go after militants using its territory to launch attacks against American troops in Afghanistan.
On the Pakistani side, officials are fed up with Washington's constant demands for more without addressing Islamabad's concerns or sufficiently appreciating the country's sacrifice. Pakistan has lost thousands of troops fighting a domestic Taliban insurgency fueled partly by resentment of the U.S. alliance.
Panetta's comments about the bin Laden raid may have been unscripted, but others he made while in India and Afghanistan seemed calculated to step up pressure on Pakistan. He stressed Washington's strong relationship with India -- which Islamabad considers its main, historic enemy -- and defended unpopular American drone attacks in Pakistan.
He also said in unusually sharp terms that the U.S. was running out of patience with Islamabad's failure to go after the Pakistan-based Haqqani network, considered the most dangerous militant group fighting in Afghanistan.
Many analysts believe Pakistan is reluctant to target the Haqqanis and other Afghan militants based on its soil because they could be useful allies in Afghanistan after foreign forces withdraw, especially in countering the influence of India.
Over the past 18 months, the relationship between the U.S. and Pakistan has suffered repeated crises.
In November, American airstrikes killed 24 Pakistani troops at two Afghan border posts. The U.S. has said it was an accident, but the Pakistani army claims it was deliberate.
Pakistan retaliated by kicking the U.S. out of a base used by American drones and closing its border to NATO supplies meant for troops in Afghanistan. Negotiations to reopen the supply route are slow but under way.
But Pakistani officials have said the route will not reopen without some kind of apology. The U.S. has expressed its regret over the incident but has refused to apologize for fear it could open the Obama administration to GOP criticism.