US intelligence agencies have been guilty of four general types of error — or more, depending on counting rules. The most costly type of error is a failure to recognize and pull together “actionable” intelligence in time to foil bad surprises. Type I errors are typically abetted by compartmentalization within the intelligence community. The failure “to connect the dots” prior to 9/11 wasn’t new; it used to be characterized as failing to detect signals in noise, as particularized in Roberta Wohlstetter’s masterful book, Pearl Harbor: Warning and Decision. A subset of this type of error is being unable to detect well-established, covert nuclear weapon programs, like Saddam Hussein’s prior to the first Gulf war.

Type II errors are the reluctance or inability to predict the possibility of pleasant surprises, which become possible when leaders change, when they realize dead-end policies, or when they mess up. It’s hard to predict good news. Leaders open to changing course remain surrounded by those who have survived by not taking risks or by engaging in bad behavior. Besides, strategic culture doesn’t change on a dime, so risk-takers have to send mixed messages, signaling new possibilities while protecting their flanks.

A subset of this type of error is assessing the existence of a well-established covert nuclear weapon program when it may have been halted by decision, incompetence, or dysfunction. Examples include Saddam Hussein’s Iraq prior to the second Gulf War and Muammar Qaddafi’s Libya.

Predicting more of the same is always a safer course than predicting the possibility of diplomatic breakthroughs – especially since the latter can brand the intelligence analyst as being hopelessly naïve. Did the US intelligence community see the course-correction in Burma coming, or was it as wrong as the Kremlinologists who misread Gorbachev? As noted earlier in this space, US Iran watchers and proliferation cynics may have gotten Rouhani wrong, as well – we’ll see.

Type III errors occur with the zealous collection of data that does far more harm to US diplomacy and international standing than might be gained from preventing bad surprises. This error is now a daily occurrence, enabled by new information-retrieval technologies and the lingering effects of suffering massive attacks on the US homeland over a decade ago. One measure of how much 9/11 remains with us is the reluctance of a President steeped in Constitutional Law to pare back the National Security Agency’s appetite for collecting and storing metadata on American citizens.

Type IV errors relate to discounting the possibility of paranoid behavior by bunkered adversaries. The presumption at work here, sometimes tested by those seeking to burnish their hardline credentials, is that bad actors won’t over-act, even when the US jerks their chains. This type of error was most egregiously on display in 1983, when some in the Reagan Administration were oblivious to the possible consequences of pursuing initiatives to keep the Kremlin off-balance. The US intelligence community, which found it difficult to distinguish between paranoid and aggressive Soviet behavior, failed to raise cautionary flags. For those interested in the particulars of this Year of Living Dangerously, check out the National Security Archives’ treasure trove of files about Able Archer.

The Obama Administration, chastened by ill-conceived, costly, and poorly executed wars in Afghanistan and Iraq — the surge in Iraq being successful only on a timescale irrelevant to larger consequences — is unlikely to engage in Type IV errors anytime soon, whether or not the intelligence community speaks up.

The commingling of Type IV and Type II errors makes it hard to explore whether the potential for positive developments exists below layers of paranoia and pathology. Making overtures to reduce nuclear dangers in such cases requires heroic efforts to establish footholds for those not locked into enemy images, to relax the grip of those who are, and to assure allies and friends dubious of risky diplomacy. This would be as hard to do for North Korea in the future as it is now for Iran. Leaders who accept this challenge can expect very little help from intelligence agencies.