ISLAMABAD - If Pakistan's May 11 parliamentary elections unfold according to recent national opinion surveys, two-time prime minister Nawaz Sharif will once again take power in Islamabad. Deposed in a 1999 coup led by General Pervez Musharraf, Sharif fled for nearly a decade of Saudi-sponsored exile. Today, however, it is Musharraf who lives under house arrest just outside Islamabad and faces charges of treason. Even in the context of Pakistan's topsy-turvy politics, this latest role-reversal is nothing short of breathtaking.

Sharif is no stranger to Washington, and by all accounts, the Pakistan Muslim League-Nawaz (PMLN) leader knows how to hold a grudge. The years of generous U.S. support to the Musharraf regime that sent him packing are bound to rankle. Time, along with a changed administration in the White House, may have started to heal that wound, but Sharif would return to power with little trust or affection for the United States.

Pakistan's political transition comes at a critical juncture for the region. The U.S.-led campaign in neighboring Afghanistan has shifted from surge to downsizing. The U.S.-Pakistan relationship has moved from the post-9/11 era to an uncertain new post-bin Laden era, and the Obama administration is busy reassessing how best to manage its long-term goals in South Asia, from counterterrorism to nuclear nonproliferation. In the midst of such flux, Islamabad's new leadership team will play an important role in setting the tone and direction of the bilateral relationship.

Sharif Versus America

Along with a bitter history, Sharif has other differences with Washington. Above all, he has publicly opposed the U.S. counterterror campaign in South Asia, and especially the CIA-directed drone war in Pakistan's tribal belt bordering Afghanistan. As Sharif has said numerous times, "We won't tolerate these attacks on our territorial jurisdictions."

It is possible that Sharif, if he returns to power, would never back up those words with meaningful action. Instead, like his predecessors, he could privately or tacitly permit U.S. drone strikes while criticizing them in public and leaving the details to be sorted out by Pakistan's military.

On the other hand, Sharif might actually try to end or curtail the scope of the drone program. Less likely, but still conceivably, he could offer a trade: his endorsement of a limited number of drone strikes in exchange for greater Pakistani control over targeting decisions. In any event, Washington should be prepared for the possibility that Sharif will seek to renegotiate the terms of Pakistan's counterterror cooperation.

A similar renegotiation may be necessary with respect to the U.S. strategy in Afghanistan. To start, although the massive retrograde of U.S. military equipment planned for the next several years is possible without Pakistan's roads and ports, it would be faster and cheaper to flow containers and vehicles south through Karachi than north through Central Asia. A new Sharif government might try to hike the price of overland transit as a new source of revenue or as bargaining leverage to achieve other goals.

Beyond logistical considerations, there is the question of just how helpful (or harmful) Sharif's Pakistan would be as the United States seeks an exit from the Afghan war. The answer depends on (1) how Sharif and his party relate to the Taliban and other violent extremist groups, and (2) whether Sharif would exert control over Pakistan's foreign policy in ways the most recent civilian government could not. 

Sharif and the Jihadis

Sharif's liberal Pakistani critics speak darkly of his associations withextremist networks in Punjab. Some say that he harbors ideological or religious sympathies for groups like the Ahle Sunnat Wal Jamaat (ASWJ), a political front for one of Pakistan's most violent Sunni extremist groups, the Sipah-e-Sahaba Pakistan (SSP). The SSP and its affiliates are responsible for horrific sectarian carnage. Recently, a series of photos has made the rounds on the Internet, showing Rana Sanaullah, a top official in Sharif's PMLN party, palling around with AWSJ leader Maulana Muhammad Ahmed Ludhianvi.

Those more sympathetic to the PMLN tend to argue that Sharif's center-right PMLN simply cuts rational, politically necessary deals with a range of Pakistan's Islamist parties to win elections. At heart, they insist, Sharif and other top party bosses are Punjabi centrists and industrialists who appreciate that extremism, violence, and anti-Western ideologies are all bad for business.

Maybe so, but U.S. officials will recall the 2010 episode when Nawaz Sharif's younger brother, Shahbaz Sharif, number two in the party and then chief minister of Punjab province,suggested that the Pakistani Taliban should have no cause to attack his province. As he explained, both the PMLN and the Taliban had rejected Musharraf's dictatorial rule as well as the "external dictation" of the United States, so they had little cause for quarrel. Even today, the PMLN's election manifesto mainly blames a combination of Musharraf's authoritarian rule and the post-9/11 U.S. war in Afghanistan for encouraging and emboldening Pakistan's militants. If the United States is hoping for a loyal partner or champion of anti-extremist causes in Islamabad, it will be sorely disappointed if the PMLN comes to power.

Over the past decade, Pakistan's violent extremists have shown a capacity to disrupt society with acts of terrorism, like the October 2012 attack on the young schoolgirl Malala Yousafzai. Fortunately, these vicious groups continue to lack political unity or a base of popular support sufficient to win power through the ballot box. One of America's chief concerns about a PMLN-led government is that its leaders seem too eager to temporize with Pakistan's home-grown extremists, too willing to offer them breathing space and even a share of political power that would turn them into an even more formidable threat to national stability.

Is there any silver lining for the United States? Actually, the PMLN's history of accommodating extremist groups might prove tactically useful at a time when Washington is energetically exploring reconciliation talks with the leaders of the Afghan Taliban insurgency. It is unlikely that Sharif's government would be able to bridge the divide between these warring adversaries, but U.S. officials should at least test the proposition.

Sharif and the Generals

More than the civilian president or prime minister, it is Pakistan's army chief who has always set Islamabad's stance on Afghanistan. How Sharif manages relations with General Ashfaq Parvez Kayani (and with Kayani's successor, since the chief is slated to retire in November) will have important implications for Pakistan's stability as well as for its relations with Afghanistan, India, and the United States.

Decades ago, Sharif and his party were the army's favorites, but their relations are now poisoned by a history of political confrontation and personal antagonism that goes well beyond Sharif's feud with Musharraf. If the two sides remain at loggerheads, their skirmishing will distract the country from necessary initiatives required for peace, security, and economic growth.The United States would then be hard-pressed simply to navigate between feuding politicians and generals.

Fortunately, many members of the PMLN are eager to overcome past grievances and find a stable working relationship with their military counterparts. If that effort were to succeed, the army and the PMLN might again prove natural partners, backed by Pakistan's "silent majority" of center-right nationalists. All have an interest in promoting economic reforms that would bolster industrial production. In addition, they seek a normalized relationship with India that permits greater trade, even if they are not ready to resolve underlying diplomatic disputes.

A Workable Relationship?

Many analysts predict that if Sharif returns to power, his party will sit atop a fractious coalition government that will tie the aging "lion of Pakistan" in political knots even if he escapes debilitating tangles with the army. No doubt, Sharif will find Pakistan a difficult country to govern; there is no telling how long his government would hold together in the face of severe stresses within and without. Sharif lacks at least some of the cunning and uncanny survival instinct that permitted President Asif Ali Zardari to keep his party in power for a full five-year term.

The United States, too, will find no easy solutions for many of its longstanding frustrations with Pakistan if Sharif assumes the helm.

U.S. officials should begin their dealings with a new Sharif government by actively encouraging his strengths, especially his economic and educational reform agenda and his openness to improved relations with India; quietly holding a firm line on areas of dispute, like drones; and exploring potential areas for tactical cooperation, such as the Afghan Taliban reconciliation effort. Under such circumstances, the best Washington can achieve would be a workable relationship: a far cry from the ambition of "strategic partnership" touted early in the Obama administration's first term, and yet not a complete disaster either.