Correction: An earlier version of this review said that Jeh Johnson, then the top lawyer at the Pentagon, and Stephen Preston, former CIA general counsel, wrote a memo providing the legal justification for the targeted killing of the American-born radical imam Anwar al-Awlaki. The memo was written in large part by Department of Justice attorneys Martin Lederman and David Barron. This version has been corrected.

“Power Wars: Inside Obama’s Post-9/11 Presidency” by Charlie Savage (Little, Brown)

Dina Temple-Raston is NPR’s counterterrorism correspondent and the author of four books on civil liberties and justice in the age of terror.

I had a taste recently of how fear shapes governments’ responses to terrorism. Visiting Brussels to cover the aftermath of the Paris attacks, I found soldiers in the streets and an armored personnel carrier outside our hotel. Officials were searching frantically for Salah Abdeslam, a Belgian-born Frenchman suspected of helping plan the Nov. 13 attacks. From my room, I watched as soldiers in camouflage moved buses into intersections and occupied Grand Place, the central square in Brussels. Government officials asked Belgians to refrain from tweeting the details of what was unfolding beneath me, which was just as well: The whole episode proved to be a false alarm. If Paris was rattled after the Islamic State attacks on its stadiums, concert halls and cafes, Brussels was in abject panic. And that fear had begun to take a political dimension.

It is against this backdrop that New York Times reporter Charlie Savage has published a new book, “Power Wars,” which scores the Obama administration on its responses to what was left of President George W. Bush’s war on terror.

By Savage’s account, the decisions the Obama administration has made with respect to national security policy stem from a single event: the failed attempt by al-Qaeda’s arm in Yemen to bring down a Northwest Airlines flight over Detroit on Christmas Day in 2009. “For Obama and his politically appointed national security team, the entire episode became the functional equivalent of the 9/11 terrorist attacks, which had transformed the Bush-Cheney administration,” Savage writes. “The result of the stomach-churning near miss of a mass murder over American soil and its political fallout would have profound implications for Obama’s legal policy, hardening his administration’s approach to counter-terrorism.”

The attempted Christmas attack involved a young Nigerian student named Umar Farouk Abdulmutallab and a new, undetectable bomb that al-Qaeda’s branch in Yemen had developed. Abdulmutallab hid the bomb in his underwear, but it failed to properly ignite and never got further than burning the seat beside him. Even so, it sent a frisson through the Obama administration.

By way of example, Savage writes that before the Christmas incident, Obama was keen to move as many prisoners as he could out of the U.S. detention center at Guantanamo Bay, something he promised to do during the presidential campaign. After the attempted attack, though, partly because the bomb plot originated in Yemen, Obama put a moratorium on repatriating Yemeni detainees. What was less understood at the time was that Yemenis made up a large portion of the men held at the prison in Cuba, so Obama’s moratorium hamstrung his efforts to close it.

Savage describes a meeting between Obama’s then-national security adviser, John Brennan, and King Abdullah of Saudi Arabia in which they discussed the problem of repatriating Yemeni detainees. “The king suggested an alternative idea for reducing the risk of letting them go,” Savage writes. “Why not implant electronic chips in the detainees’ bodies, allowing their movements to be tracked? This had been done with horses and falcons, he said. ‘Horses don’t have good lawyers,’ Brennan replied.”

While the issue of closing the Guantanamo facility comes up throughout the book, Savage doesn’t shed light on one of the great mysteries surrounding the effort to shutter the prison: how it was that the Obama administration didn’t take office with a plan. Obama had made closing Guantanamo a signature issue in the campaign, and obviously it was something he would have to address early on. Why wasn’t there a clearly delineated strategy? Why wasn’t Attorney General Eric Holder put in charge of the effort?

Critiques of the Bush administration’s war on terror typically fall into two camps: one focused on civil liberties and the other on rule of law. For the civil libertarians, the problem with the Bush administration was that it appeared to strike the wrong balance between rights and national security. Those more focused on rule of law took issue with the way that balance was struck — without congressional or judicial oversight. Obama has had to try to appeal to both groups.

Savage makes the case that Obama was never in the civil liberties camp. His followers put him there. “President Obama and most of his people appeared in practice to care somewhat more about civil liberties than President Bush and most of his team,” Savage writes. “But the Obama team was not, and never had been, the full-throated civil libertarians that Senator Obama had allowed and encouraged his supporters in the Democratic primary campaign to think — and his opponents to fear — they would be.”

To experienced watchers of national security policy, all this will sound vaguely familiar and merely add detail to what is already known. What Savage contributes to the broader discussion is his careful behind-the-scenes reporting.

He reveals, for example, that after the Defense Department’s top lawyer, Jeh Johnson, and the CIA general counsel Steve Preston finished reviewing a classified memo providing what they thought was the legal justification for the targeted killing of the American-born radical imam Anwar al-Awlaki – the man thought to have ordered the Christmas Day attack -- they discovered from a law professor’s blog post that the memo neglected to address a foreign-murder statute. They asked the two Justice Department attorneys who wrote the memo, Martin Lederman and David Barron, to rework it.

“The decision sent anxiety through the national security establishment,” Savage writes. “Johnson and Preston sought and received reassurances that the first memo remained good law in the meantime, in case the United States found al-Awlaki before they finished. Over the next few months, [Lederman and Barron] would produce dozens of drafts, and the replacement grew to six times the length of the original.”

The great strength of “Power Wars,” and sometimes its weakness, is its methodical, exquisitely detailed chronicling of the back-and-forth between principals and deputies as they crafted policy. That said, one can’t help wishing at times that Savage had chosen to tell this story by focusing on a handful of characters and their roles in the events rather than writing an exhaustive catalogue. Sometimes it is difficult to discern, for example, whether a bit player who appears early in the book will be an important player later.

Even so, there is no more comprehensive guide to today’s debates over national security and civil liberties than “Power Wars.”

Critics of the Obama administration say the president is legitimizing practices that fly in the face of the very thing he claimed he wanted to accomplish during his first campaign: to bring post-9/11 practices in line with international law and pull back on the reins of executive power. But to be fair, as the past two months have proved, nothing can change the debate as quickly as an attack.

The shooting in San Bernardino is a case in point. For two years there had been a national conversation about the intelligence community’s over-collection of information to find terrorists, but just hours after the California attack, the question posed was just the opposite: Why, people asked, did authorities know so little about the shooters behind it?

Power Wars
Inside Obama’s Post-9/11 Presidency

By Charlie Savage

Little, Brown. 769 pp. $30