“Be modest about what military force can accomplish and what technology can accomplish,” Gates said.

He urged his audience to have an “appreciation of limits” of military power, arguing that although the U.S. has achieved huge advances in targeting and intelligence that have made attacks more precise, warfare is “inevitably tragic, inefficient and uncertain.”

The comments amounted to a critique of a military theory called “effects-based operations,” which argues in part that the government can carefully craft military interventions to have a predictable impact.

“Look askance at idealized, triumphalist or ethnocentric notions of future conflict that aspire to upend the immutable principles of war: where the enemy is killed, but our troops and innocent civilians are spared,” he said.

The above from Defense Secretary Robert Gates.