President Barack Obama may have inherited the war on terrorism from his predecessor, but in some ways the stakes have only grown since he took the decision maker’s seat in the Oval Office. In his new book, Kill or Capture: The War on Terror and the Soul of the Obama Presidency, Newsweek and Daily Beast reporter Daniel Klaidman draws on extensive research, including interviews with more than 200 sources, including current and former officials in the Obama administration, to work his way into the president’s mind as Obama learned what it meant to fight a shadowy enemy in the 21st century.

In the aftermath of 9/11 and the wars in Afghanistan and Iraq, America’s enemies seemed both everywhere and nowhere. Some of the tactics that would prove most effective over the following years, such as drone strikes and cross-border raids, drew criticism at home and abroad. Obama the former constitutional law scholar has demonstrated a willingness to continually rethink the way America is dealing with the threat posed by religious extremists.

The Daily Beast collects seven moments in the wartime education of Barack Obama.

1.  Faces to the names

The war against a global enemy in the information age has meant that the president can know more than ever before about the persons against whom he chooses to authorize a strike. Klaidman recounts an early meeting between the then-Democratic candidate and Richard Clarke, a principal counterterrorism adviser from the Bush administration. “As president, you kill people,” Clarke said to the senator from Illinois. An inscrutable Obama looked back at Clarke, Klaidman writes, not betraying any emotion. “I know that,” Obama told Clarke in an even tone. “He didn’t flinch,” Clarke later said of the meeting.

Early in his term, Obama became incensed upon learning about “signature strikes”—the practice of eliminating targets who bore the characteristics of terrorists but about whom there was little other information. Targets were not necessarily positively identified before the strikes took place, and people in Pakistan in particular, where many of the strikes occurred, were furious. “That’s not good enough for me,” Obama said when the practice was explained to him.

2. Kill or Capture: The false choice

George W. Bush may have said that Osama bin Laden was wanted “dead or alive,” but the many issues raised by the prospect of capturing the terrorist and bringing him to justice meant that there was really only one option. The Obama administration found that the same was true of its hunt for other top terrorists, Klaidman reports. “We never talked about this openly, but it was always a back-of-the-mind thing for us,” a top Obama counterterrorism adviser told Klaidman regarding the administration’s deliberations over whether it should focus on detaining or eliminating targets. “Anyone who says it wasn’t is not being straight.”

One terrorist Obama was reportedly particularly set on seeing killed or captured was Anwar al-Awlaki, an American citizen and radical cleric who was killed by a drone in Yemen last September. Al-Awlaki obsessed Obama after the success of the attack on bin Laden, Klaidman reports, telling advisers at a weekly counterterrorism meeting, “I want Awlaki. Don’t let up on him.” According to sources, the president even considered allowing for some collateral damage if it meant taking out Awlaki, asking that advisers keep him apprised of any opportunity to eliminate the cleric.

3. A White House divided

As the Obama administration went head-to-head with terrorists, fault lines within the White House began to appear as senior officials moved to protect their own bailiwicks. After an incident that involved efforts by the White House to place a political operative named Chris Sautter on Attorney General Eric Holder’s staff, Obama adviser and campaign strategist David Axelrod heard that Holder was spreading word of Sautter’s hiring. “I’m not Karl Rove,” Axelrod growled at Holder in a hallway confrontation. Valerie Jarrett had to step in to keep the feud from escalating.

The close relationship between the president and the attorney general became the subject of envy for the other cabinet-level advisers, sources told Klaidman. “Of all of the 12 cabinet members, why does the boss like Eric the most?” one of the administration’s advisers asked sarcastically. “We should all throw him in a pit and kick him.”

4. ‘Baseball cards’

The hunt for an elusive enemy took its toll on Harold Koh, the former Yale Law professor and State Department legal adviser who shuffled through what were called “baseball cards”—the presidentially authorized hit list. “It was an unlikely turn for one of the more respected human-rights lawyers of his generation,” Klaidman writes. “At Yale Law he has memorized the names and faces of his students, bright-eyed idealists who wanted to use the law to improve the world. Now he was studying government hit lists, memorizing the profiles of young, vacant-eyed militants, and helping determine which ones could be put to death.”

Koh would be presented with the classified PowerPoint slides, and would often have less than an hour to flick through them and determine whether or not the government had the legal authority to take out the target. Apart from the militants’ physical characteristics, a photo, and other basic data, the slides detailed whether the intelligence on them came from HUMINT or SIGINT–human or electronic surveillance. They also detailed the specific terrorist actions in which the target was believed to have taken part.

5. The hitch strikes again

The late Christopher Hitchens scored a hit with his Vanity Fair piece recounting what it was like to be waterboarded, reaching Attorney General Holder and influencing his decision to launch an investigation into the way the US interrogated its detainees. In his 2008 column “Believe Me, It’s Torture,” the polemicist wrote about his staged abduction at a location tucked away somewhere in North Carolina. After reading the article, Holder was reportedly entranced by the accompanying video, which showed the (rather out-of-shape) Hitchens hold out for a little more than10 seconds before breaking under the torture technique. “Watching the video,” Klaidman writes, “Holder was both mesmerized and repulsed.”

The article and video spurred Holder to look more closely at the interrogation tactics of the Bush era, and he was “increasingly convinced that he would need to launch an investigation, or at least a preliminary inquiry to determine whether a full-blown probe was warranted.”

6. Clinton sticks to her guns

Obama has been faulted for not, as president, maintaining the optimism he embodied on the campaign trail. In at least one instance, however, Secretary of State Hillary Clinton rebuked high-ranking national-security officials for the way they were handling the case of Khalid Sheikh Mohammed, the alleged architect of the 9/11 attacks and a Guantánamo detainee.

Obama had pledged to close Guantánamo and to try suspects, whenever possible, in civilian trials and not in front of military commissions. With the officials wavering on these points, Clinton reportedly got tough. “We would be throwing the president’s commitment to close Guantánamo into the trash bin,” she said at a White House meeting. “We are doing him [the president] a disservice by not working harder on this.”

7. Transfer of power

A president must weigh the power of precedent. In a 2009 meeting with advisers, Obama voiced concerns about what a future president may do with the power to indefinitely detain suspected terrorists. Alluding to the FDR-era Supreme Court decision that allowed the president to intern American citizens of Japanese descent during World War II, Obama worried about the powers his actions may place in the hands of a future president.

“You never know who is going to be president four years from now,” Obama said. “I have to think about how Mitt Romney would use that power.”

                    –The Daily Beast