After the fusillade of accusations and denials between Washington and Islamabad, things remain pretty much the same as before.

Precisely a decade after the 9/11 attacks, US-Pakistani relations appeared for a moment to have come full circle. As the ruins of the World Trade Center smoldered, then-Deputy Secretary of State Richard Armitage read Pakistan the riot act, threatening war if Islamabad did not turn against its Taliban allies in Afghanistan. In his memoirs, Pervez Musharraf describes how Armitage crudely warned that failure to comply with Washington’s demands meant that Pakistan would be bombed “back to the Stone Age.”

The uncharacteristically blunt charges leveled two weeks ago by Admiral Mike Mullen, the outgoing chairman of the U.S. Joint Chiefs of Staff, do not reach the rhetorical standard set by Armitage. But they are startling enough given how assiduously he had worked to maintain good relations with the Pakistani military establishment, especially the powerful chief of army staff, General Ashfaq Parvez Kayani. Mullen’s statement sparked a fierce war of words between Washington and Islamabad, prompting policy experts to debate whether their epically dysfunctional relationship was this time actually at the point of rupture, and leading some Pakistanis to conclude that the United States was on the warpath with their country.

In testimony before the Senate Armed Services Committee, Mullen asserted that “the government of Pakistan and most especially the Pakistani army” along with its Inter-Services Intelligence agency have chosen “to use violent extremism as an instrument of policy” in an effort to exert strategic influence in Afghanistan. In particular, he charged that the Haqqani network, the brutal mafia enterprise/militia group that has emerged as the most formidable insurgent force in Afghanistan, operates as “a strategic arm” of ISI. He further stated that the network, acting “with ISI support,” was responsible for a series of recent high-profile attacks, including the June 28th assault on the Intercontinental Hotel in Kabul, the September 10th truck bombing at a U.S. base in nearby Wardak province that wounded 77 NATO troops, and the September 13th day-long strike on the U.S. embassy and NATO headquarters in Kabul.

Of course, Mullen was only giving voice to what had long been obvious: Pakistan has been an egregiously duplicitous ally in Afghanistan, serving as a vital logistical conduit for U.S. forces fighting there all the while supporting the insurgent groups that have killed and maimed hundreds of these very same soldiers.

During the 2008 presidential campaign, Barack Obama took heat for saying that he would be prepared to order unilateral military action in Pakistan if that country failed to act on its own against Islamic militants. And just a week before Obama’s inauguration, Vice President-elect Joe Biden visited Pakistan and pointedly asked Kayani whether the two countries even “had the same enemy as we move forward.”

But once the administration took office, it has preferred to express its mounting frustrations with Islamabad in private. Just this past March, Secretary of State Hillary Rodham Clinton officially certified to Congress that Pakistan was showing a “sustained commitment” to fighting terrorism, a declaration that was necessary to release the next tranche of military aid to Islamabad.

Mullen, more than anyone else in Washington, labored mightily to implement this behind-the-scenes preference. He calls himself “Pakistan’s best friend,” and has met with Kayani dozens of times in recent years, including hosting in August 2008 an unusual summit abroad the aircraft carrier USS Abraham Lincoln as it cruised the Indian Ocean. So, his public calling-out was a sharp departure from administration practice. And to reinforce his point, reports surfaced a few days after his testimony – almost certainly from Pentagon sources – alleging that Pakistani border guards had deliberately assaulted a group of U.S. military officers in May 2007 and that Kayani has personally assured the new NATO commander in Afghanistan that he would interdict the plot to attack the base in Wardak.

To be sure, Mullen did not issue a direct ultimatum in the way Armitage did, and it is very unlikely that one was delivered behind the scenes. Still, at the very least, his comments seem to portend a further ratcheting-up of U.S. military activities inside Pakistan. Speaking alongside Mullen at the Senate hearing, Defense Secretary Leon E. Panetta emphasized that “We’ve made clear that we are going to do everything we have to do to defend our forces.”

Indeed, the trend toward greater unilateral action has been visible for some time now.  Afghan militias, backed by the Central Intelligence Agency, have carried out covert missions in Pakistan’s tribal areas for several years. The Raymond Davis affair earlier this year showed that the CIA, frustrated with the quality of information provided by the Pakistani security services, has started to forge its own intelligence-gathering networks in the country. And the lightning commando raid in Abbottabad, undertaken without Kayani’s coordination or even consent, was definitive confirmation of Washington’s increasing willingness to do without Pakistani cooperation and conduct military operations on its own.

Some predict that Washington will now resort to sending special-forces teams into the badlands of North Warizistan, where the Haqqani leadership is ensconced. But it is more likely that the Obama administration will extend its preferred strategy of drone warfare in dealing with militant groups that are resident on Pakistani territory. Until this point, Miranshah, the main town in North Warizistan, has been off limits to drone attacks due to the close proximity of Haqqani fighters with the civilian populace and Pakistani security forces. This restriction is likely to be relaxed.

Pressure is building on Capitol Hill for even further action. Diane Feinstein (D-CA), chairman of the Senate Intelligence Committee, and Carl Levin (D-MI), chairman of the Senate Armed Services Committee, have called for placing the Haqqani network on the State Department’s list of foreign terrorist organizations. This action, which is being considered by the administration, may help alleviate the clamor to also declare Pakistan a state sponsor of terrorism, something that the White House is desperate to avoid since it would entail a complete collapse in relations. But blacklisting the Haqqani network will have little practical effect since the organization’s top leadership has already been designated as terrorists.

A growing chorus of legislators is also demanding drastic cuts in U.S. military and economic assistance to Pakistan and that funding be made specifically conditional on Islamabad’s reining in of the Haqqani clan. Senator James Risch (R-ID) speaks for many when he says “I think Americans are getting tired of it as far as shoveling money in there at people who just flat out don’t like us.” In the House of Representatives, Congressman Ted Poe (R-TX) calls Pakistan “disloyal, deceptive and a danger to the United States,” and is championing legislation that would freeze aid to the country.

But there are sharp limits on Washington’s room to maneuver, starting with the fact that the long supply lines running through Pakistan are pivotal to the on-going conduct of military operations in Afghanistan and that Islamabad is key to the conflict’s political endgame. The White House’s efforts this week to temper Mullen’s remarks (here and here) demonstrate the force of these constraints. A Pakistani newspaper has quoted a US diplomat in Islamabad as saying that “the worst is over” and that both countries continue to agree that a breakdown in ties “is not an option.” And the Obama administration has even reportedly reassured Pakistan that it would not send ground forces into North Warizistan.

Further complicating U.S. action is the dense fog surrounding Pakistan’s exact relationship with the legion of militants that operate from its territory. It’s clear that ISI relies on Haqqani operatives to safeguard Pakistani interests in Afghanistan. But there are major questions as to whether the group is simply a pliable proxy, essentially responsive to ISI’s command and control, or whether it is a fundamentally independent outfit that Islamabad occasionally supports but is also too afraid to confront directly. Mullen has alluded to these uncertainties and in an interview a few days ago Obama conceded that “the intelligence is not as clear as we might like in terms of what exactly that relationship is.”

With the Haqqani leadership close allies of Al Qaeda, the September 13th siege of the U.S. embassy and NATO headquarters could very well have been pay-back for bin Laden’s death, timed for the tenth anniversary of the 9/11 attacks, and aided by Pakistani elements wanting to avenge the embarrassment of Abbottabad. But this action also runs counter to Islamabad’s efforts in recent months to mend relations with Washington. Pakistan has a habit of delivering up militant leaders – including, most famously, Khalid Sheikh Mohammad – in order to appease bouts of U.S. anger. A month after the Abbottabad raid, Ilyas Kashmiri, whom the United States last year labeled a “specially designated global terrorist,” was killed by a drone strike in South Warizistan. According to one media source, the targeting information may have come from the ISI.

Nor is it clear why the Pakistani military establishment would connive at such a brazen provocation, especially when the U.S. exit from Afghanistan is already in progress. President Obama has just reiterated his commitment to withdraw some 40,000 troops by next summer, and so time is clearly on Islamabad’s side in terms of shaping the future dispensation in Kabul. The date of the September 13th attacks is also problematic considering that General Kayani was scheduled to participate in a NATO conference in Spain just days afterwards. Pakistani officials must have known that Admiral Mullen, also in attendance, would use the occasion to confront Kayani in person (see also photo above).

Mullen’s public statements have elicited indignant denials and defiant warnings from Pakistan. But Islamabad’s options are sharply limited as well. Even if American forces are on the way out of Afghanistan, Washington is still in a strong position to make things difficult for the cash-strapped Pakistanis. Responding to Congressional demands, the Obama administration could withhold additional aid flows, like it did in July when it suspended $800 million in military assistance. It could also block the International Monetary Fund loans that Islamabad says it does not need this year but will almost certainly require in 2012.

Pakistan could always try to ward off U.S. coercion by threatening to cut off the routes that supply U.S. troops in Afghanistan, but this is a diminishing option as Washington increasingly expands its logistics network through Russia and Central Asia.  It would also mean hurting army-linked businesses that profit from the heavy traffic along these lines.

Pakistani elites talk bravely – and even bizarrely – about further cementing strategic links with China. Prime Minister Yousef Raza Gilani waxes lyrically about ties with Beijing being “higher than mountains, deeper than oceans, stronger than steel and sweeter than honey.” After the Abbottabad mission, Islamabad sought a formal military pact with Beijing and crowed about offering the Chinese navy use of the Gwadar port, only to be rebuffed on both counts. As if on cue, China’s public secretary minister, Meng Jianzhu, showed up in Islamabad earlier this week, with Rehman Malik, his Pakistani counterpart, declaring that “China is always there for us in the most difficult of times.” Tellingly however, the Chinese media was more focused on the inaugural session of the China-India economic dialogue than on Meng’s trip. Beijing’s concern about the activities in Xinjiang of Pakistan-based Islamic militants have dampened Islamabad’s appeal as a strategic partner, as has the news – announced just after Meng’s visit – that a Chinese mining company is abandoning what was to be Pakistan’s largest foreign-investment project due to security concerns.

And for all of Islamabad’s harsh rhetoric, it is significant that ISI’s chief, Lieutenant General Ahmed Shuja Pasha, told a gathering of Pakistan’s politicians the other day that relations with Washington must not be allowed to breakdown.

So, after days of sound and fury in both capitals, where do things stand? Pretty much the same as before. Despite growing frustration and exasperation, the Obama administration has little choice but to carry on with its engagement of Pakistan. Indeed, for all of his exasperation, Mullen himself made this same point in his Senate testimony, noting that “despite deep personal disappointments in the decisions of the Pakistani military and government, I still believe that we must stay engaged.”

As he and others in Washington realize, the words that then-US ambassador in Islamabad Anne W. Patterson wrote in early 2009 still apply:

“The relationship is one of co-dependency we grudgingly admit – Pakistan knows the U.S. cannot afford to walk away; the U.S. knows Pakistan cannot survive without our support.”

Also true is the cliché that Gilani glibly employed last week to describe the American predicament: “They can’t live with us. They can’t live without us.” With the United States beginning its pull-out from Afghanistan, Islamabad will have every incentive to continue relying on its jihadi allies to fill the resulting vacuum, while Washington will remain dependent upon Pakistani influence to secure a minimally-acceptable political settlement.