The death of Saudi Crown Prince Sultan after a long illness begins the kingdom’s royal succession process, a family affair with major implications for the stability of the nation and the region.

Sultan was an institution. He became minister of defense and aviation for the kingdom in 1962 when Bob McNamara was John F. Kennedy’s secretary of defense. Every President since JFK has dealt with him. He built an extremely expensive army and air force with billions of dollars of purchases from America and Europe, but he was always reluctant to use it in combat. For Sultan, wars were better fought by your allies than by your own troops.

He was a consummate intriguer who loved to plot and scheme against the House of Saud’s many enemies. The CIA was often his partner. He usually prevailed, but if his plans failed he would not hold grudges. In the mid-1990s he tried to oust Yemeni President Ali Abdullah Saleh in a civil war. Saleh won the war, and Sultan reconciled with his foe.

He could out smart America, too. Sultan sent his son Prince Bandar to China in the 1980s to buy long-range missiles to hit Tehran, but hid the deal from the CIA until the missiles were dug in deep in the desert so Washington could not upset the deal—which broke nonproliferation rules we supported. We protested, and then got over it.

I negotiated with him often, including to build a gigantic air base deep in the desert for U.S., U.K., and French jets, which were named after him. He ensured our total security after pro-Iranian Shiite terrorists blew up a U.S. barracks in the Saudi city of Khobar. At Prince Sultan Air Base, no terrorist could get anywhere near us.

His half brother, King Abdullah, is also ill, so the next crown prince could be king sooner rather than later. Minister of Interior Prince Nayef is the favorite. Abdullah may want the choice ratified by the Allegiance Council he created a few years ago, an assembly of the three dozen heirs (males only) of the kingdom’s founder, Sultan’s father, King Abdul Aziz. That would signal that Abdullah’s efforts to reform the absolute monarchy will continue.

Nayef is much more conservative than either Abdullah or Sultan, and much more suspicious of America—especially after the Arab Spring. He holds grudges forever. But Nayef also hates Iranians and all Shiites, and his son and deputy minister has become a ruthless foe of al Qaeda. Nayef’s spies foiled the terror group’s plot to blow up two aircraft over Chicago just a year ago. In short, we can work with him like we have with Sultan—with a wary eye.

Nayef’s challenge will be to navigate the Arab awakening. The Saudis are counterrevolutionaries and have been for more than a half century. They blame Obama for letting former Egyptian president Hosni Mubarak fall from power, and are furious at his trial in Cairo. They sent in their own troops to stop the revolution in Bahrain. They have told Jordan’s King Abdullah that they will not allow reforms next door in his kingdom. In Yemen they want another strong man to replace Saleh.

They want America to deal with Iran and al Qaeda, but they don’t share our freedom agenda. They are very close to Pakistan—in part to have a nuclear ace just in case they need a bomb for their Chinese missiles. They have ties to the Taliban, the Muslim Brotherhood, Hamas, and many other Islamist parties—ties Nayef has handled for decades.

In some ways, the kingdom’s Nayef era has already begun. Sultan has been too ill for years to run affairs effectively, and Abdullah is fading. America will need to find common ground for continued cooperation with Nayef’s kingdom even as we disagree about democracy’s future in Arabia.