MINOT AIR FORCE BASE, N.D. (AP) — The trouble began at Minot Air Force Base in North Dakota.

It's torn at the core of the nuclear Air Force and compelled two of the last three secretaries of defense to ask: Who's minding the store?

Minot has had its share of bad publicity about nuclear weapons foul-ups, followed by hard questions from Washington about why it and other nuclear bases are caught in a recurring cycle of trouble and recovery.

Back in 2007, jaws dropped at news that six nuclear-tipped cruise missiles were flown across the country by mistake aboard a B-52 bomber.

The air crew was oblivious and the people accountable for the weapons at their starting point at Minot did not know they were missing.