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.”