Not only are both Bhutto and Musharraf incapable of delivering what they are promising each other after months of secret, back-channel dealings that have been promoted by the United States and Britain, the agreement, if it is struck, may prove to be more divisive and destabilizing than unifying. “This deal is bound to promote confrontation and divisiveness,” says retired Pakistani Army Lt. Gen. Talat Masood. “It’s counterproductive to the objectives of moderation and national reconciliation that the U.S. envisioned in the deal.” Or as political scientist and columnist Hasan Askari Rizvi put it, “This deal is only going to create a lot of trouble for Pakistan.”

Perhaps that’s what happens when deal-making takes place in a foreign country (almost all the talks are taking place in the U.K.) and doesn’t take into account Pakistan’s complex political character. Key players in both Bhutto’s Pakistan People’s Party and Musharraf’s ruling Pakistan Muslim League party are adamantly opposed to the agreement, which could potentially rip their organizations apart. Some PPP stalwarts believe that Bhutto is compromising the party’s liberal principles by doing a deal with, and casting a lifeline to, a man they see as a military dictator. Important players in the PML, which is largely made up of defectors from the PPP and former prime minister Nawaz Sharif’s party, fear that the deal will undercut their present stranglehold on power in parliament and the provinces. They have quietly vowed to sabotage it. “People controlling the party are warning Musharraf that if you sign the agreement with Benazir there will be a revolt,” says Rizvi.

Indeed, a recalcitrant PML could scupper the deal. Bhutto wants Musharraf to convene parliament, which the PML and its allies control, in the next few days and have it pass two constitutional amendments as confidence-building measures before the presidential election takes place. One would allow a two-time prime minister such as Bhutto to serve a third term. The other would remove the president’s draconian powers to dissolve parliament. Musharraf’s ruling party favors neither. What’s more, both Musharraf and his party want the president to be reelected by parliament before tackling the amendments Bhutto wants. But Bhutto fears that once Musharraf is reelected he may be reluctant, or unable, to deliver on his amendment promises.

Sequencing is not the only stumbling block. The president’s men want him to be reelected while still serving as army chief and not resign his commission, as Bhutto demands. Even if he does promise to resign in the future—and his aides emphasize that no such decision has been made—no one, certainly not Bhutto, can guarantee the president’s reelection, even though he controls the necessary majority votes in parliament and the state assemblies. The Supreme Court could conceivably rule later this month that Musharraf cannot concurrently hold both offices or that he’s simply ineligible to serve another term.

Adding to the volatile mixture is the imminent arrival of the other exiled prime minister, Nawaz Sharif, a political force whom Bhutto and Musharraf have pointedly, and perhaps stupidly, left out in the cold. In one of its first judgments last month, the newly independent-minded Supreme Court ruled that Sharif, who was overthrown in Musharraf’s bloodless 1999 coup and went into exile in 2000, could return home. If he does, or even tries, he could present Musharraf with his biggest political challenge ever. Sharif is still popular in the Punjab, Pakistan’s most populous and powerful province, and “he still has strong standing in the military,” according to Masood. On Thursday Sharif announced at a London press conference that he would be arriving in Islamabad on Sept. 10 and would then proceed to his hometown of Lahore in a massive political procession.

Musharraf’s options for damage control are limited. If he allows Sharif to land, the former prime minister could be met by hundreds of thousands of enthusiastic supporters at the airport and the surrounding city of Rawalpindi. If Musharraf doesn’t allow Sharif’s plane to touch down, the large crowds assembled to greet him could riot, causing potentially destabilizing violence. The president would also infuriate the Supreme Court if he turns Sharif’s plane away. If Sharif does successfully return and the procession passes through the heartland of Musharraf’s PML on its way to Lahore then, predicts Rizvi, “that will shake the foundation” of the president’s party.

Clearly, the Bhutto-Musharraf deal, even if it’s announced next week, guarantees them nothing. The moment the president files his reelection papers in the next few days, anti-Musharraf protestors will doubtless take to the streets. The Supreme Court will take up the several petitions opposing his reelection, and Sharif will be winging his way back to the country. “Sweat is starting to gather on Musharraf’s brows already,” says respected political columnist Ayaz Amir. Pakistan is embarking on a very a bumpy and historic ride indeed over the next few days and weeks.