Making love to a cactus: U.S.-Pakistan relations at a dangerous moment This is a critical moment for the United States's most fraught diplomatic challenge. Pakistani officials arrive in Washington this week for meetings designed to shore up a relationship that is both vital and exceedingly dangerous for both regimes. The Pakistani delegation will nominally be led by the country's foreign minister, Shah Mahmood Qureshi. But the real focus will be the man who many feel is so powerful that the fact he is not yet president reflects only a personal choice on his part. As Pakistan's top military officer, General Ashfaq Parvez Kayani might as well be known as General Plan B. If the current government stumbles, if unrest spreads, U.S. officials are fully counting on him to step in and put a lid on the problem. The conversations this week will be publicly focused on gestures of support for the Pakistanis from the U.S. government, from beefing up civilian and military aid to generating public statements of common purpose. But behind the scenes there will be palpable tension. The United States is dissatisfied -- the feeling being that Pakistan is not doing everything it can to assist in tracking down extremist groups living within their borders. That discomfort undoubtedly is not eased by the exclusive report in Britain's Guardian today that is entitled, "Pakistan intelligence services 'aided Mumbai terror attacks.'" The story describes a 109-page Indian government report based on the interrogation of David Headley; the Pakistani-American arrested in relation to the Mumbai attacks. "Under questioning," writes Jason Burke, "Headley described dozens of meetings between officers of the main Pakistani intelligence service, the ISI, and senior militants from the Lashkar-e-Taiba (LeT) group responsible for the Mumbai attacks." While the perspectives provided by Headley offer just one view and include a number of statements suggesting that senior ISI officials may not have been plugged into the entire Mumbai plan, they corroborate much of what has long been suspected about ties between the ISI and extremist groups. Further, they tell an unsettlingly logical story of how the Mumbai attacks were undertaken as part of a deliberate strategy by the historically more regionally-focused Lashkar-e-Taiba to remain relevant in a world in which competing terrorist groups were attracting members seeking the grander mission of jihad against the West. It is a nauseating image: officials of a government nominally allied to the United States working with terrorists to plan a murderous attack on innocents as a marketing ploy on behalf of their stone cold terrorists of choice. Nauseating, but despite Pakistani denials that it is baseless, with the unmistakable ring of truth. The contrast between the meetings and the report reveal the core conundrum the Obama administration faces with regard to Pakistan. No country is home to more urgent risks. While near the top of the list of those risks are the presence and day-to-day violent agenda of al Qaeda, Lashkar-e-Taiba and other such militant organizations, at the very top is that the rational elements in the Pakistani government might lose control of some or all of the country's nuclear arsenal. The United States seeks to shore up those rational elements -- led in a practical sense more by Kayani than civilian officials -- and collaborate with them in addressing the threats that President Obama himself has famously likened to a "cancer." But in so doing, the United States must embrace a government that is fractured -- divided in and against itself (within every sub-unit it seems, you find another split). In fact, within the ISI and elsewhere among Pakistan's power structure, there are forces that are among the most direct enemies of the United States, the most vital allies of al Qaeda, the most important supporters the Taliban ever had. Circumstances have dictated that to contain and seek to undercut those forces, the United States and its allies have had to engage the other, moderate side of the house. In short, the United States must, in order to pursue its most vital interests, make love to a cactus. This is realpolitik at its most stark, loaded, and complex. And it underscores that within every compromise or look the other way associated with the "swallow-hard and pursue the national interest" dimension of realpolitik there are the seeds of the strategy's own destruction. Embrace flawed allies and the relationship turns on whether it is driven by the objectives of the alliance or the flaws that are being overlooked in its favor. And -- as we have seen from Saigon to Baghdad to tin pot dictatorships worldwide -- more often than not the flaws win out in the long run. The fragility of this relationship and the tensions associated with it will be on display in the meetings this week -- perhaps more visible in what is unsaid -- body language and via indirection -- than in what is actually said in the open. But so much is riding on the success of the delicate diplomacy involved here and the United States's leading spokespeople -- like Secretary of State Hilary Clinton and the U.S. point man for South Asia, Richard Holbrooke -- who are so famously forthright that it is likely there will be a number of very candid and blunt exchanges as well. All of this is made even more crucial not only because the administration fears that should another major terrorist episode emanate from Pakistan that the entire fragile enterprise could become undone, but because the circumstances surrounding the relationship are now changing in important ways. The United States wants out of neighboring Afghanistan in the worst way â€¦ and typically when you want something in the worst way, you get it in the worst way. The Afghanistan government appears to making a place for our former enemies, the Taliban, and thus is beginning to look very much like the Pakistani regime in terms of its divisions -- so much so that it will likely be linked to and guided by elements within that Pakistani government -- and not the ones we are most comfortable with. Next, there will be a tension because of another factor. Next month, President Obama will be going to India. Historically, due to India's Cold War ties to the U.S.S.R., the United States embraced Pakistan for strategic reasons. But for even more compelling historical reasons -- from roots in the British Empire to the embrace of democracy to a host of cultural affinities -- India, not Pakistan, is the United States's natural ally in South Asia. India is also a rising major power and an important counterweight to China. Since the late Clinton years, the United States has been turning ever closer to New Delhi and that is a trend the Obama visit will and should continue. Given India and Pakistan's history of conflict -- accentuated again by the Mumbai-attack focus of the Guardian report -- the United States is about to wrap its gnarliest diplomatic relationship in a fabric of even greater complexities. It is what the United States must do, to be sure. The Obama administration has in fact, thus far handled all this with considerable dexterity (no small feat considering the factors involved and the fact that this is the first time in history that South Asia policy has topped the list of U.S. foreign policy priorities). But one cannot help but wonder if -- given the underlying forces at play -- the biggest challenges we face lie in the future.