defining who terrorist are and what they look like.

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.

Now there  is no clear definition of what a terrorist looks like. The terrorist in the newest terror attack did not consist of the usual make up of what previous groups of terrorist looked like.

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.”

“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.”

“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.”

“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.”

““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.”

““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?””