The new caution among US intelligence officials reflects adherence to what some now call “the Powell Rule.”

For more than three years, American intelligence officials have insisted that they learned from their mistakes in the months leading to the Iraq war, when murky information about Saddam Hussein’s weapons programs was presented as fact and inconclusive judgments were hardened into statements of near certainty.

The more calibrated intelligence assessments that have come to light in recent weeks, particularly on Iran and North Korea, appear to show a new willingness by American spy agencies to concede the limits of their knowledge.

The new caution reflects adherence to what some officials now call “the Powell Rule.” That rule is intended to avoid a repetition of former Secretary of State Colin L. Powell’s humiliation after the satellite photos and intercepted communications he presented to the United Nations Security Council as proof that Iraq was stockpiling banned weapons turned out to be nothing of the sort.

Read more at Spiegel