In another major blow to al-Qaeda, a U.S. drone strike last Monday in the North Waziristan tribal area of Pakistan killed the organization’s new number two commander, Atiyah Abd al-Rahman. The successful strike demonstrates the importance of continuing the drone missile campaign along Pakistan’s border with Afghanistan as a cornerstone of the mission to degrade and eventually defeat al-Qaeda.

Pakistani officials and media outlets regularly criticize the drone missile strikes as a violation of Pakistani sovereignty. But the U.S. is highly unlikely to relent in its drone campaign since the tactic has proven to be the most effective tool for the U.S. to destroy al-Qaeda’s leadership and disrupt its ability to plot and train for attacks across the globe.

Al-Rahman, a Libyan national, had risen to al-Qaeda’s number two spot following the elimination of Osama bin Laden on May 2. In addition to serving as the primary liaison to al-Qaeda’s organizational networks in Iraq and Iran, al-Rahman had bolstered al-Qaeda’s position in Algeria by helping form al-Qaeda in the Islamic Maghreb.

The elimination of al-Rahman—a central operational planner for the organization—is another sign that al-Qaeda is weakening. Al-Rahman had directed American terrorist Bryant Neal Vinas, who helped al-Qaeda with a plot to bomb the New York City subway in 2009. Al-Rahman had also directed terrorist plots in Europe and played a role in the suicide bombing that killed seven CIA operatives in Afghanistan in December 2009.

Files captured at bin Laden’s Abbottabad compound apparently revealed that bin Laden and al-Rahman had discussed trying to broker a deal with Pakistani authorities for al-Qaeda to receive protection in Pakistan in exchange for its agreement to refrain from mounting attacks inside Pakistan. While there are no indications that such a plan was ever muted with Pakistani officials, the revelation shows that al-Qaeda operatives perceive vulnerabilities among Pakistan’s leadership that they can exploit to their advantage.

While the U.S. has made tremendous strides against al-Qaeda in the last 18 months, culminating in the death of bin Laden in May, it will not be able to finish the job of defeating the organization altogether without full Pakistani cooperation.

Pakistani officials have long tolerated terrorist groups that are linked to al-Qaeda, which in turn facilitate the organization’s ability to use Pakistan as a launch pad for its international terrorist campaign. Pakistani officials have sought to argue that they can “better control” or “keep tabs on” the terrorist groups if their intelligence agencies retain links to them. However, if such groups were able to protect the world’s most wanted terrorist without the Pakistan military’s knowledge, who is keeping tabs on whom?

As the Heritage Foundation Counterterrorism Task Force has argued in its August 24 report, U.S. officials should reject Pakistani assertions that they are incapable of shutting down groups linked to al-Qaeda, such as the Lashkar-e-Taiba, which is responsible for the 2008 Mumbai terror attack, and the Harakat-ul-Mujahideen, whose leader was in contact with bin Laden’s courier before the May 2 raid.

Indeed, the U.S. should never settle for Pakistani excuses for avoiding a full-throttle approach against these terrorist groups and instead demand that Pakistan be accountable for the activities of all terrorist groups on its soil.

Despite the severe differences between Islamabad and Washington over terrorism, it is in the interest of the U.S. to remain engaged with Pakistani leaders and demonstrate U.S. interest in the development of a prosperous and moderate Pakistan free of the terrorist scourge. Pakistani leaders are slowly waking to the costs of tolerating terrorism on their soil, and the U.S. should be in a position to support the state against the terrorists’ designs.