The Caliph Ibrahim, also known as Abu Bakr al-Baghdadi, is the most important new figure in the world of terrorism in years. Ibrahim Awwad Ibrahim al-Badri, his real name, aspires to lead the global jihad movement in the creation of a new Islamic caliphate here and now. In practice, he has divided the global jihadists into warring camps and created a civil war in their murderous ranks.

‘The believer,’ his nickname, is the subject of a rich and important portrait by William McCants in the latest Brookings Essay. In it, we learn that Baghdadi is a product of Iraq’s tormented and violent recent history. One of his brothers died in the eight-years-long Iran-Iraq war that killed a couple hundred thousand Iraqis. Baghdadi escaped that fate due to nearsightedness. His first mentor in jihad was an Iraqi veteran of the war against the Soviets in Afghanistan in the 1980s. Baghdadi was an early supporter of the notorious founder of al-Qaida in Mesopotamia, Abu Musab al-Zarqawi, who bears much of the responsibility for starting the country’s civil war between Sunni and Shia.

If Baghdadi is the epitome of the jihadi terrorism that sweeps the Islamic world today, the epitome of the counterterrorists fighting back is the new crown prince of Saudi Arabia. Prince Muhammad bin Nayef (or MBN, as he is known) was educated to be a counterterrorist. After studying in Oregon, he spent several years with the FBI and Scotland Yard. His father served as the Kingdom’s minister of interior for over three decades and groomed his son to replace him.

Muhammad bin Nayef has excelled in the job. He led the campaign to defeat al-Qaida inside the Kingdom between 2003 and 2006, the most violent challenge to the House of Saud in the last century. He has escaped several assassination attempts by al-Qaida. In one, the assassin feigned surrender to get close enough to the prince and then blew himself apart with a hidden bomb.

In the process, MBN has become a favorite of America’s security and intelligence services. George Tenet, Leon Panetta, and John Brennan all sing his praises. He has foiled several terrorist attacks on the United States, including one plot to attack Chicago.

Most recently, his operatives captured Ahmed Ibrahim al-Mughassil, the mastermind of the 1996 terrorist attack on an American air base in Khobar, Saudi Arabia, in which 19 American airmen were killed and 300 injured. The Saudi and American intelligence services have been trying to capture al-Mughassil for almost 20 years. Last month, the Saudis nabbed him as he got off a flight from Tehran to Beirut where he planned to attend his son’s wedding and swiftly flew him to the Kingdom. Once again, Prince Muhammad bin Nayef demonstrated his skill as the prince of counterterrorism. Al-Mughassil could be a unique source of information on Iranian support for terrorist groups, including Hezbollah.

MBN is now poised to be the first of his generation of royals to ascend to the throne. For the last 60 years, the sons of the modern Kingdom’s founder, Ibn Saud, have ruled. King Salman will be the last. If the King sticks with MBN, it will be his time when the 79 year old Salman passes away. But Salman has already shuffled the line of succession once this year and may do it again to benefit his son, Deputy Crown Prince Muhammad bin Salman.

For now, MBN is the heir to the throne. While the king has been in France and Morocco this summer, MBN has run the government at home. When the king visited Washington last week, MBN minded the store at home. His story is the subject of my Brookings Essay, “The Prince of Counterterrorism.”