This was the enemy, served up in the latest chart from the intelligence agencies: 15 Qaeda suspects in Yemen with Western ties. The mug shots and brief biographies resembled a high school yearbook layout. Several were Americans. Two were teenagers, including a girl who looked even younger than her 17 years.
President Obama, overseeing the regular Tuesday counterterrorism meeting of two dozen security officials in the White House Situation Room, took a moment to study the faces. It was Jan. 19, 2010, the end of a first year in office punctuated by terrorist plots and culminating in a brush with catastrophe over Detroit on Christmas Day, a reminder that a successful attack could derail his presidency. Yet he faced adversaries without uniforms, often indistinguishable from the civilians around them.
"How old are these people?" he asked, according to two officials present. "If they are starting to use children," he said of Al Qaeda, "we are moving into a whole different phase."
It was not a theoretical question: Mr. Obama has placed himself at the helm of a top secret "nominations" process to designate terrorists for kill or capture, of which the capture part has become largely theoretical. He had vowed to align the fight against Al Qaeda with American values; the chart, introducing people whose deaths he might soon be asked to order, underscored just what a moral and legal conundrum this could be.
Mr. Obama is the liberal law professor who campaigned against the Iraq war and torture, and then insisted on approving every new name on an expanding "kill list," poring over terrorist suspects' biographies on what one official calls the macabre "baseball cards" of an unconventional war. When a rare opportunity for a drone strike at a top terrorist arises — but his family is with him — it is the president who has reserved to himself the final moral calculation.
"He is determined that he will make these decisions about how far and wide these operations will go," said Thomas E. Donilon, his national security adviser. "His view is that he's responsible for the position of the United States in the world." He added, "He's determined to keep the tether pretty short."
Nothing else in Mr. Obama's first term has baffled liberal supporters and confounded conservative critics alike as his aggressive counterterrorism record. His actions have often remained inscrutable, obscured by awkward secrecy rules, polarized political commentary and the president's own deep reserve.
In interviews with The New York Times, three dozen of his current and former advisers described Mr. Obama's evolution since taking on the role, without precedent in presidential history, of personally overseeing the shadow war with Al Qaeda.
They describe a paradoxical leader who shunned the legislative deal-making required to close the detention facility at Guantánamo Bay in Cuba, but approves lethal action without hand-wringing. While he was adamant about narrowing the fight and improving relations with the Muslim world, he has followed the metastasizing enemy into new and dangerous lands. When he applies his lawyering skills to counterterrorism, it is usually to enable, not constrain, his ferocious campaign against Al Qaeda — even when it comes to killing an American cleric in Yemen, a decision that Mr. Obama told colleagues was "an easy one."
His first term has seen private warnings from top officials about a "Whac-A-Mole" approach to counterterrorism; the invention of a new category of aerial attack following complaints of careless targeting; and presidential acquiescence in a formula for counting civilian deaths that some officials think is skewed to produce low numbers.
The administration's failure to forge a clear detention policy has created the impression among some members of Congress of a take-no-prisoners policy. And Mr. Obama's ambassador to Pakistan, Cameron P. Munter, has complained to colleagues that the C.I.A.'s strikes drive American policy there, saying "he didn't realize his main job was to kill people," a colleague said.
Beside the president at every step is his counterterrorism adviser, John O. Brennan, who is variously compared by colleagues to a dogged police detective, tracking terrorists from his cavelike office in the White House basement, or a priest whose blessing has become indispensable to Mr. Obama, echoing the president's attempt to apply the "just war" theories of Christian philosophers to a brutal modern conflict.
But the strikes that have eviscerated Al Qaeda — just since April, there have been 14 in Yemen, and 6 in Pakistan — have also tested both men's commitment to the principles they have repeatedly said are necessary to defeat the enemy in the long term. Drones have replaced Guantánamo as the recruiting tool of choice for militants; in his 2010 guilty plea, Faisal Shahzad, who had tried to set off a car bomb in Times Square, justified targeting civilians by telling the judge, "When the drones hit, they don't see children."
Dennis C. Blair, director of national intelligence until he was fired in May 2010, said that discussions inside the White House of long-term strategy against Al Qaeda were sidelined by the intense focus on strikes. "The steady refrain in the White House was, ‘This is the only game in town' — reminded me of body counts in Vietnam," said Mr. Blair, a retired admiral who began his Navy service during that war.
Mr. Blair's criticism, dismissed by White House officials as personal pique, nonetheless resonates inside the government.
William M. Daley, Mr. Obama's chief of staff in 2011, said the president and his advisers understood that they could not keep adding new names to a kill list, from ever lower on the Qaeda totem pole. What remains unanswered is how much killing will be enough.
"One guy gets knocked off, and the guy's driver, who's No. 21, becomes 20?" Mr. Daley said, describing the internal discussion. "At what point are you just filling the bucket with numbers?"
‘Maintain My Options'
A phalanx of retired generals and admirals stood behind Mr. Obama on the second day of his presidency, providing martial cover as he signed several executive orders to make good on campaign pledges. Brutal interrogation techniques were banned, he declared. And the prison at Guantánamo Bay would be closed.
What the new president did not say was that the orders contained a few subtle loopholes. They reflected a still unfamiliar Barack Obama, a realist who, unlike some of his fervent supporters, was never carried away by his own rhetoric. Instead, he was already putting his lawyerly mind to carving out the maximum amount of maneuvering room to fight terrorism as he saw fit.
It was a pattern that would be seen repeatedly, from his response to Republican complaints that he wanted to read terrorists their rights, to his acceptance of the C.I.A.'s method for counting civilian casualties in drone strikes.
The day before the executive orders were issued, the C.I.A.'s top lawyer, John A. Rizzo, had called the White House in a panic. The order prohibited the agency from operating detention facilities, closing once and for all the secret overseas "black sites" where interrogators had brutalized terrorist suspects.
"The way this is written, you are going to take us out of the rendition business," Mr. Rizzo told Gregory B. Craig, Mr. Obama's White House counsel, referring to the much-criticized practice of grabbing a terrorist suspect abroad and delivering him to another country for interrogation or trial. The problem, Mr. Rizzo explained, was that the C.I.A. sometimes held such suspects for a day or two while awaiting a flight. The order appeared to outlaw that.
Mr. Craig assured him that the new president had no intention of ending rendition — only its abuse, which could lead to American complicity in torture abroad. So a new definition of "detention facility" was inserted, excluding places used to hold people "on a short-term, transitory basis." Problem solved — and no messy public explanation damped Mr. Obama's celebration.
"Pragmatism over ideology," his campaign national security team had advised in a memo in March 2008. It was counsel that only reinforced the president's instincts.
Even before he was sworn in, Mr. Obama's advisers had warned him against taking a categorical position on what would be done with Guantánamo detainees. The deft insertion of some wiggle words in the president's order showed that the advice was followed.
Some detainees would be transferred to prisons in other countries, or released, it said. Some would be prosecuted — if "feasible" — in criminal courts. Military commissions, which Mr. Obama had criticized, were not mentioned — and thus not ruled out.
As for those who could not be transferred or tried but were judged too dangerous for release? Their "disposition" would be handled by "lawful means, consistent with the national security and foreign policy interests of the United States and the interests of justice."
A few sharp-eyed observers inside and outside the government understood what the public did not. Without showing his hand, Mr. Obama had preserved three major policies — rendition, military commissions and indefinite detention — that have been targets of human rights groups since the 2001 terrorist attacks.
But a year later, with Congress trying to force him to try all terrorism suspects using revamped military commissions, he deployed his legal skills differently — to preserve trials in civilian courts.
It was shortly after Dec. 25, 2009, following a close call in which a Qaeda-trained operative named Umar Farouk Abdulmutallab had boarded a Detroit-bound airliner with a bomb sewn into his underwear.
Mr. Obama was taking a drubbing from Republicans over the government's decision to read the suspect his rights, a prerequisite for bringing criminal charges against him in civilian court.
The president "seems to think that if he gives terrorists the rights of Americans, lets them lawyer up and reads them their Miranda rights, we won't be at war," former Vice President Dick Cheney charged.
Sensing vulnerability on both a practical and political level, the president summoned his attorney general, Eric H. Holder Jr., to the White House.
F.B.I. agents had questioned Mr. Abdulmutallab for 50 minutes and gained valuable intelligence before giving him the warning. They had relied on a 1984 case called New York v. Quarles, in which the Supreme Court ruled that statements made by a suspect in response to urgent public safety questions — the case involved the location of a gun — could be introduced into evidence even if the suspect had not been advised of the right to remain silent.
Mr. Obama, who Mr. Holder said misses the legal profession, got into a colloquy with the attorney general. How far, he asked, could Quarles be stretched? Mr. Holder felt that in terrorism cases, the court would allow indefinite questioning on a fairly broad range of subjects.
Satisfied with the edgy new interpretation, Mr. Obama gave his blessing, Mr. Holder recalled.
"Barack Obama believes in options: ‘Maintain my options,' " said Jeh C. Johnson, a campaign adviser and now general counsel of the Defense Department.
‘They Must All Be Militants'
That same mind-set would be brought to bear as the president intensified what would become a withering campaign to use unmanned aircraft to kill Qaeda terrorists.
Just days after taking office, the president got word that the first strike under his administration had killed a number of innocent Pakistanis. "The president was very sharp on the thing, and said, ‘I want to know how this happened,' " a top White House adviser recounted.
In response to his concern, the C.I.A. downsized its munitions for more pinpoint strikes. In addition, the president tightened standards, aides say: If the agency did not have a "near certainty" that a strike would result in zero civilian deaths, Mr. Obama wanted to decide personally whether to go ahead.
The president's directive reinforced the need for caution, counterterrorism officials said, but did not significantly change the program. In part, that is because "the protection of innocent life was always a critical consideration," said Michael V. Hayden, the last C.I.A. director under President George W. Bush.
It is also because Mr. Obama embraced a disputed method for counting civilian casualties that did little to box him in. It in effect counts all military-age males in a strike zone as combatants, according to several administration officials, unless there is explicit intelligence posthumously proving them innocent.
Counterterrorism officials insist this approach is one of simple logic: people in an area of known terrorist activity, or found with a top Qaeda operative, are probably up to no good. "Al Qaeda is an insular, paranoid organization — innocent neighbors don't hitchhike rides in the back of trucks headed for the border with guns and bombs," said one official, who requested anonymity to speak about what is still a classified program.
This counting method may partly explain the official claims of extraordinarily low collateral deaths. In a speech last year Mr. Brennan, Mr. Obama's trusted adviser, said that not a single noncombatant had been killed in a year of strikes. And in a recent interview, a senior administration official said that the number of civilians killed in drone strikes in Pakistan under Mr. Obama was in the "single digits" — and that independent counts of scores or hundreds of civilian deaths unwittingly draw on false propaganda claims by militants.
But in interviews, three former senior intelligence officials expressed disbelief that the number could be so low. The C.I.A. accounting has so troubled some administration officials outside the agency that they have brought their concerns to the White House. One called it "guilt by association" that has led to "deceptive" estimates of civilian casualties.
"It bothers me when they say there were seven guys, so they must all be militants," the official said. "They count the corpses and they're not really sure who they are."