Updated

At what point do breakdowns in discipline put the country's nuclear security in jeopardy?

And when does a string of embarrassing episodes in arguably the military's most sensitive mission become a pattern of failure?

Defense Secretary Chuck Hagel is now concerned "there could be something larger afoot here," according to his chief spokesman, and "wants this taken very, very seriously."

The disclosures of disturbing behavior by nuclear missile officers are mounting and now include alleged drug use and exam cheating. Yet Air Force leaders insist the trouble is episodic, correctible and not cause for public worry.