EVERY fresh Pakistan-US crisis raises questions about the viability of this partnership. Given the nature and frequency of crises this year alone, many expert voices have argued that we have reached the breaking point.

In fact, some wonder why ties have not ruptured to date in light of all that has gone on. The same questions are being asked now, in the wake of the Nato strike.

Very simply, the underlying factors that have forced the two sides to continue the engagement despite major hiccups still hold firm. Principal among these is the desire to avoid an all-out civil war in Afghanistan. Those who believe that a rupture is all but certain underestimate just how important an amicable Afghan settlement remains to both parties.

For the US, the 2014 security transition in Afghanistan remains the number one foreign policy concern in the region for now. And the need for Islamabad and Washington to work together on Afghanistan will only grow as this date draws nearer.

There is a fairly candid admission by policymakers on both sides, at least in private, that there are no potent alternatives to a joint Pakistan-US effort at reconciliation in Afghanistan. Notwithstanding the popular belief to the contrary, I haven't found any serious thought creeping into official decision-making which sees wisdom in trying to bypass the other side on the reconciliation process. Of course, both are hedging their bets — competing while cooperating — but this is to be expected; it is classic brinkmanship aimed at enhancing one's bargaining position.

As someone who keeps abreast of the thinking on both sides, it is fairly obvious to me that decision-makers in the two capitals are desperate to avoid a rupture in the relationship for fear that a complete divorce would all but seal Afghanistan's descent into further chaos. And they are right.

Recount Pakistani and US behaviour in the wake of the recent crises and you'll find ample evidence suggesting conscious efforts to set things right behind the scenes even when ties seemed to be headed for disaster.

There is a discernible pattern to crisis events: a crisis occurs; the public sentiment is enraged (depending on which side is presumably wronged); the respective governments point to that to gain concessions from the other side; the media frenzy all but convinces people that something will give this time round; yet, the official enclaves, after making popular noises start pulling back and commence attempts behind closed doors to put things back on track. All because the primacy of keeping the partnership, however troubled, going holds true for both parties.

If the engagement has to continue, as I argue, certain parameters will be met.

From the US side, monetary assistance has long been upheld as the moniker of American commitment and support to Pakistan. And while the real impact on the economy or Pakistan's security performance is a matter of debate, symbolically, a cut off or even drastic reduction in aid would signal to Pakistanis a US desire to pull back from the partnership.

Most US lawmakers are still persuaded on this count. They are therefore unlikely to pull the plug on Pakistan in the immediate future. The frustration and complaints will continue — in fact grow — but not in a way that it actually leads to blocking the assistance.

Second, the US engagement with the Pakistani military top brass and the on-ground tactical cooperation will remain intact. As much as Washington would like to focus attention on the civilians, GHQ's hold on the Afghan policy is well understood. Even apart from a grand strategy on reconciliation, Pakistan's control over the supply routes and the day-to-day need for intelligence cooperation necessitates continued cooperation with the Pakistan Army.

On the Pakistani side too, the decision-makers understand the compulsions to continue security cooperation. Supply routes, some level of intelligence cooperation, a blind eye to drones and even border coordination will have to remain part of the mix if the two sides are to stick together.

Also, the need for continued engagement implies that Pakistan will do its best to remain relevant to the situation in Afghanistan, and not only through its nuisance value but through continued efforts to facilitate the reconciliation process.

This has thus far been the murkiest part of the entire 'endgame' picture for most. Just how much Pakistan has been able to contribute is unclear. In any case, the onus is on Pakistan to prove its leverage in nudging the Taliban towards negotiations. In fact, the need to prove its relevance will only increase as 2014 approaches and the international community becomes more desperate for results.

Sceptics would surely see my take on the situation as too optimistic. They would probably point out that each crisis has made the partnership weaker and that the post-crisis arrangement is always a somewhat downgraded one.

But there is another way to see this.

While crises have undoubtedly lead to much finger-pointing and revoked offers on cooperative arrangements (Shamsi airbase being the latest example), such downgrading may well be in the interest of a more durable engagement. Odds are that certain downward corrections in what is on offer from each side and clear communication of red lines, capabilities and the will to cooperate and candid admission of policy preferences may make for a much more honest relationship. It would be a pleasant change if the two sides agreed to realistic goals and expectations rather than continuing to over-commit, only to be accused of all sorts of malicious intent when they fail to deliver.

Let me not leave you with the impression that all is well with the Pakistan-US relationship. There is no question that it is on shaky grounds. But it is dangerous to consider it so flimsy that one stops feeling the need to continue investing in it. The more we see this as a relationship waiting to break, the more likely both sides will be to take steps that make it a self-fulfilling prophecy. And if I am right that Pakistan-US coordination is critical for Afghanistan's future, it is easy to see why such an outcome should be avoided at all costs.

The writer is South Asia adviser at the US Institute of Peace, Washington, D.C.