Washington - Beyond the Air Force's embarrassing suspension of 17 nuclear missile launch officers lie two broader questions.

Do those entrusted with the world's most destructive weapons feel stuck in a dead-end career field, given the momentum toward more nuclear arms reductions? And is there a morale crisis among these officers?

This matters because the missiles - 450 of them standing in below-ground silos, ready for launch at a moment's notice - form a critical part of America's nuclear defenses. There is little room for error. Although none has ever been fired in anger, the risk of accidental launch or unauthorized intrusion is real.

In a rare look inside the secretive world of nuclear missiles, The Associated Press reported this past week that the deputy commander of operations for the 91st Missile Wing at Minot Air Force Base, N.D., complained to his officers about "rot" within their ranks.

In a confidential email obtained by the AP, Lt. Col. Jay Folds wrote of 17 launch officers, 10 percent of his force, being removed from duty for what he likened to incompetence. They are being given remedial training, with the goal of being back on duty within two months.

"If you have this many officers who failed, then how do you explain that and who should be held accountable for their failure?" Robert Gates, a former defense secretary, said Friday. "I think those questions clearly need to be answered."

When faced with similar questions during his Pentagon tenure, Gates fired the top two Air Force leaders in 2008. That followed a series of nuclear embarrassments, including the inadvertent transport of six nuclear-tipped missiles on a B-52 bomber, whose pilot did not know they were aboard when he flew from Minot to Barksdale Air Force Base, La.

Gates said in an interview Friday before addressing graduates of the University of South Carolina in Columbia, S.C., that he was disappointed by the latest revelations but confident that Minot's weapons were not in jeopardy.

The Minot missile wing is responsible for 150 Minuteman 3 missiles, one-third of the Air Force's entire ICBM force.

Inside the missile launch capsules, so called because of their pill-like shape, two officers stand watch, authorized to turn the keys enabled by secret launch codes if the presidential order ever comes. They are 60 feet underground, electronically linked to 10 silos, each with one armed Minuteman 3.

That is a lot of responsibility for the young lieutenants and captains that the Air Force puts in these jobs. It's also an enormous challenge for their commanders to keep them on track - a challenge not always met.

In a March inspection the 91st wing was rated "marginal," the equivalent of a "D" grade, when tested on launch skills.

Folds described a deeper problem, citing willful rule violations such as leaving open the multi-ton blast door to their launch compartment while one of the two crew members was asleep. Sleep breaks are authorized, but the open door is not, given the risk of losing control of the capsule to an unauthorized intruder.

Publicly, the Air Force insists that its missileers, as they are known within the service, are capable, trustworthy and committed. But Air Force Secretary Michael Donley also acknowledged in congressional testimony that he worries that talk of further shrinking the nation's nuclear force is having a "corrosive effect" on his troops.

Gen. Mark Welsh, the Air Force chief of staff, said at the same congressional hearing that it's understandable that young missile officers may be demoralized by the realization that theirs is a shrinking field.

"You say, 'My goodness, there's only three (missile wings in the entire Air Force). There's no opportunity there,' " Welsh said. "That's actually not the case, but that's the view when you're" in one of those units.

Bruce Blair, a former missile launch officer and now a national security scholar at Princeton University, said Friday that morale has dropped in part because the ICBM mission that originated in 1959, deterring the Soviet Union from attacking the U.S. or Europe, is less compelling than it was generations ago.

"This dead-end career is not the result of shrinking nuclear arsenals, but rather because the Cold War ended decades ago and because so few senior commander jobs exist within the missile specialty," Blair said. "Most crews can't wait to transfer out of missiles into faster-track careers such as space operations, but the Air Force doesn't make it easy."

Donley came close to blaming the White House for any malaise. He said that when officers see "the national leadership" contemplating more nuclear reductions "this does have a corrosive effect on our ability to maintain focus on this mission." He also said "critics or others" contribute to this when they suggest getting rid of the ICBM force entirely.

This touches on a sensitive problem for the Air Force, which is inclined to defend its nuclear turf even as President Barack Obama has made clear his view that it is time to end America's heavy reliance on nuclear weapons.

"The massive nuclear arsenal we inherited from the Cold War is poorly suited to today's threats, including nuclear terrorism," he said a year ago in Seoul. He noted that in 2011 he ordered his national security team to undertake a comprehensive review of nuclear forces and policies, which was completed last year.

"We can already say with confidence that we have more nuclear weapons than we need," Obama said.

The president is expected to announce this year his intention to make new nuclear reductions, and his defense secretary, Chuck Hagel, has publicly supported the eventual elimination of all of the Air Force's ICBMs. Hagel took that stand before he became Pentagon chief in February; he has not commented on it since then.

Hagel is scheduled to meet with Donley and Welsh on Monday to press for more answers on the lapses at Minot. He received a series of staff briefings on the matter in the days following publication of the AP story, and his press secretary, George Little, said Friday that Hagel "expects not to see this kind of problem again."

Concern over deterioration in the Air Force's nuclear mission is not new.

After Gates cleaned house in 2008, an outside advisory panel headed by former Defense Secretary James Schlesinger issued a scathing report. It concluded, "There has been an unambiguous, dramatic and unacceptable decline in the Air Force's commitment to perform the nuclear mission." It put the blame mainly on Air Force leaders, not young officers.

"The readiness of forces assigned the nuclear mission has seriously eroded," the report said, adding, "We must restore pride among those who are performing the Air Force nuclear mission."

Gates said Friday the onus is on Air Force leaders to avoid decay in the nuclear force, now and in the future.

"The challenge facing the Air Force leadership, no matter what the size of the nuclear arsenal, is how do you sustain the morale and the intensity of the men and women who manage the nuclear enterprise," Gates said. "That's not an easy thing, especially during terrible budget times that they're encountering right now."