PAKISTAN’S RELEASE this month of eight long-imprisoned Taliban commanders raised hopes that Afghanistan’s moribund peace talks could be restarted. In fact, the gesture, made at the request of Afghan President Hamid Karzai, said more about the attempt by Pakistan’s new government to improve relations with Afghanistan than it did about the prospects for peace. While there is a chance for a breakthrough toward stability in Kabul in the coming months, it relies on two entirely different matters: the presidential election process just getting underway and a pending bilateral security agreement between Afghanistan and the United States.

The two are closely related, at least in the view of U.S. officials. If the security agreement can be completed by the target date at the end of October, it would give Afghans a sense of confidence as they contemplate who should replace Mr. Karzai as president following the April election. The accord would provide for U.S. trainers and Special Forces to remain in the country after the scheduled departure of all combat troops at the end of 2014. It would give Afghans sound reason to believe that their next government would not be toppled by the Taliban.

The election, in turn, could produce a new leader with broad national support, if it is free and fair. So far, preparations have gone relatively well: Mr. Karzai signed an election law drawn up by the parliament and publicly pledged last month that he would neither call off the ballot nor attempt to manipulate it for a favored candidate. Hundreds of thousands of new voters have been registered across the country. Though no presidential candidates have come forward ahead of an Oct. 6 registration deadline, that is not necessarily a bad thing: Aware that a campaign contested along sectarian or regional lines could divide the country and even trigger a civil war, factions and potential candidates are negotiating behind the scenes in an attempt to build national alliances.

At best, a solid security agreement, a commitment by President Obama and NATO to an adequate post-2014 force, and the inauguration of a new president could give the Taliban and its Pakistani backers the incentive to negotiate peace that they currently lack. However, realizing those aims will require both Mr. Karzai and Mr. Obama to set aside some grudges and excessive expectations. While the Afghan president appears to accept the imperative of granting U.S. troops immunity from local courts — the issue that blocked a U.S. military deal with Iraq — he is still demanding that the accord guarantee Afghanistan’s security and future funding for security forces. U.S. officials say Mr. Obama can’t make such commitments in what will be an executive agreement, not a treaty. Mr. Karzai’s occasional spouting of anti-American conspiracy theories doesn’t help; neither do the White House’s threats to embrace a “zero option” for U.S. forces if agreement is not reached soon.

A failure to complete a security agreement, or a failed Afghan election, would be a disaster for the United States as well as for Afghanistan. If the Obama administration can’t reach a deal with Mr. Karzai, then it should show patience, focus on promoting a free and fair election, and wait to negotiate with his successor.