He is a delusional narcissist who will fight until his last breath. Or an impulsive showman who will hop the next flight out of town when cornered. Or maybe he’s a psychopath, a coldly calculating strategist — crazy, like a desert fox.

The endgame in Libya is likely to turn in large part on the instincts of Col. Muammar el-Qaddafi, and any insight into those instincts would be enormously valuable to policy makers. Journalists have formed their impressions from anecdotes, or from his actions in the past; others have seized on his recent tirades about Al Qaeda and President Obama.

But at least one group has tried to construct a profile based on scientific methods, and its conclusions are the ones most likely to affect American policy. For decades, analysts at the Central Intelligence Agency and the Department of Defense have compiled psychological assessments of hostile leaders like Colonel Qaddafi, Kim Jong-il of North Korea and President Hugo Chávez of Venezuela, as well as allies, potential successors and other prominent officials. (Many foreign governments do the same, of course.)

Diplomats, military strategists and even presidents have drawn on those profiles to inform their decisions — in some cases to their benefit, in other cases at a cost.