The CIA first began to take a more aggressive posture during the Cold War, when presidents from Kennedy to Reagan used it to arm and train anti-Soviet opposition groups. But even then it remained mostly in the shadows, attempting to manipulate world events in the U.S.'s favor. And its primary tools -- back channels, foreign assets, secret bank accounts, and misinformation -- remained the same, even as the mission evolved. It was not until September 2001, when the U.S. quickly and dramatically changed its national security focus to terrorism, that the CIA began its slow transformation from a spy agency into something that at times more closely resembles a paramilitary organization.

How much has the CIA changed since 2001? In the late 1990s, senior officials in the Clinton administration debated endlessly over whether the CIA could legally be granted the authority to kill Osama bin Laden; the agency had been banned from assassinations since 1976, following revelations that it had tried to kill Fidel Castro a decade earlier. Even the idea of a direct presidential order to kill the world's most dangerous terrorist, a man who had already blown up two U.S. embassies, was considered controversial and outside the CIA's normal realm. Yet in the first 20 months of the Obama administration, the CIA's drone program in Pakistan alone killed over 800 people. It runs or helps run drone programs and special operations in several countries and even operates detention centers. Under Obama, the CIA and Pentagon have borrowed one another's methods in Afghanistan and Iraq (not to mention one another's leadership) so regularly that the line between U.S. intelligence and the U.S. military has blurred in unprecedented ways.

The change has also been political. In the days immediately after September 11, 2001, the Bush administration decided to put the agency on a much tighter leash, using something it called Top Secret Codeword/Threat Matrix. Intelligence reports were fed directly to the White House, which announced it would begin more directly controlling CIA activities. "The mistake was not to have proper analysis of the intelligence before giving it to the president," National Security Council member Roger Cressey told New Yorker reporter Jane Mayer for her Pulitzer-winning book on U.S. national security policy after September 2001, The Dark Side. "There was no filter. Most of it was garbage. None of it had been corroborated or screened. But it went directly to the president and his advisers, who are not intelligence experts. That's when mistakes got made."

That's also when the White House began pushing the CIA in a way that encouraged it to put less emphasis on its long-term information-collection and counterintelligence efforts, slow-boil missions that might takes years or more to yield results and that might be more about detecting future threats than combating existing ones. The White House's new urgency about terrorism and al-Qaeda placed far greater pressure on the CIA to deliver immediate results on known threats. First that meant tracking terrorists, then capturing and "interrogating" them, and within a few years it meant killing them outright. That urgency and pressure has been sustained for over a decade now. Judging by Hezbollah's recent victory over the CIA in Lebanon, which appears to have grown somewhat sloppy in its spycraft, some of the patience from the old days was lost.