In the months leading up to the killing of Usama bin Laden, veteran intelligence analyst Robert Cardillo was given the nickname “Debbie Downer.” With each new tidbit of information that tracked bin Laden to a high-walled compound in northern Pakistan — phone records, satellite imaging, clues from other suspects — Cardillo cast doubt that the terror network leader and mastermind was actually there.

As the world now knows well, President Obama ultimately decided to launch a May 2011 raid on the Abbottabad compound that killed bin Laden. But the level of widespread skepticism that Cardillo shared with other top-level officials — which nearly scuttled the raid — reflected a sea change within the U.S. spy community, one that embraces debate to avoid “slam-dunk” intelligence in tough national security decisions.

The same sort of high-stakes dissent was on public display recently as intelligence officials grappled with conflicting opinions about threats in North Korea and Syria. And it is a vital part of ongoing discussions over whether to send deadly drone strikes against terror suspects abroad — including U.S. citizens.