"He likes action, especially when he doesn’t leave fingerprints"

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.”

There is a seduction to the secret world, which for generations has charmed presidents and their advisers. It’s easier pulling the levers in the dark, playing the keys of what a CIA official once called the “mighty Wurlitzer” of covert action. Politics is a much messier process – out in the open, making deals with bullies and blowhards. But that’s the part of the job that Obama must master if he wants another term.

It’s an interesting anomaly of Barack Obama’s presidency that this liberal Democrat, known before the 2008 election for his antiwar views, has been so comfortable running America’s secret wars. Obama’s leadership style — and the continuity of his national security policies with those of his predecessor, George W. Bush — has left friends and foes scratching their heads. What has become of the “change we can believe in” style he showed as a candidate? The answer may be that he has disappeared into the secret world of the post-Sept. 11 presidency. [...]

Obama is the commander in chief as covert operator. The flag-waving “mission accomplished” speeches of his predecessor aren’t Obama’s thing; even his public reaction to the death of bin Laden was relatively subdued. Watching Obama, the reticent, elusive man whose dual identity is chronicled in “Dreams From My Father,” you can’t help wondering if he has an affinity for the secret world. He is opaque, sometimes maddeningly so, in the way of an intelligence agent. Intelligence is certainly an area where the president appears confident and bold. James Clapper, the director of national intelligence who has been running spy agencies for more than 20 years, regards Obama as “a phenomenal user and understander of intelligence.” When Clapper briefs the president each morning, he brings along extra material to feed the president’s hunger for information.

This is a president, too, who prizes his authority to conduct covert action. Clapper’s predecessor, Adm. Dennis Blair, lost favor in part because he sought to interpose himself in the chain of covert action. That encroached on Obama, who aides say sees it as a unique partnership with the CIA... Perhaps Obama’s comfort level with his intelligence role helps explain why he has done other parts of the job less well. He likes making decisions in private, where he has the undiluted authority of the commander in chief. He likes information, as raw and pertinent as possible, and he gets impatient listening to windy political debates. He likes action, especially when he doesn’t leave fingerprints.