These two books address very different sides of the same coin. Both are written by leading figures in the field: Kilcullen made his name as both a theorist and a practitioner of counterinsurgency, and Bergen has written extensively about radical Islamist groups. Kilcullen addresses the rise of the Islamic State (also known as ISIS), particularly in the Middle East, whereas Bergen concentrates on the phenomenon of Islamist radicalization inside the United States. Both subjects have taken on added urgency in the wake of recent events, notably the ISIS-related terrorist attacks last year in Paris and San Bernardino, California.
Kilcullen’s book is a tour de force. With telling details and personal reminiscences, he seeks to make sense of how the U.S. counterinsurgency campaign in Iraq—which at one point got close to at least the appearance of success—ultimately fell apart. He blames the Bush administration for the original mess, President Barack Obama for prematurely ending the U.S. military role in Iraq, and Iraqi Prime Minister Nouri al-Maliki for indulging his most sectarian instincts. Mayhem in Syria allowed the Sunni extremists of ISIS to build a base of operations, from which they swept back into Iraq. They have been repelled to some extent, but Kilcullen’s message is that matters could get worse; he warns against ever assuming that “this is as bad as it gets.”
Bergen also focuses on Sunni extremism, telling the stories of young Americans who found meaning and inspiration in jihadist propaganda and decided to devote themselves to the cause. He examines the 330 individuals charged in the United States with a terrorism-related crime since the 9/11 attacks and notes that they were not a particularly alienated or deprived bunch. Some were converts (including one former Orthodox Jew). Their normality made them hard to detect. In some cases, social media skills enabled them to develop effective online propaganda, but most of their real-world plots failed. A number acquired some notoriety, particularly the cleric Anwar al-Awlaki, whom the United States killed in a 2011 drone strike in Yemen, and Nidal Hasan, the U.S. Army major who murdered 13 people at Fort Hood in 2009. Bergen describes the FBI's efforts to keep track of would-be jihadists, which have suffered from some awkward slip-ups and from the bureau’s tendency to concoct fake plots and then encourage suspects to take part in them. Authorities must do all they can to prevent jihadist atrocities, but Bergen reminds readers that since the 9/11 attacks, an American’s chances of being killed by an ordinary person with a gun have been 5,000 times as great as the risk of being killed by an Islamist terrorist.