Air Force officers responsible for the nation's nuclear weapons arsenal cheated on a proficiency test because they felt too much pressure to perform perfectly, Air Force Secretary Deborah Lee James concluded.

"I heard repeatedly from teammates that the need for perfection has created a climate of undue stress and fear," James told reporters. "I believe that a very terrible irony in this whole situation is that these missileers didn't cheat to pass, they cheated because they felt driven to get 100 percent, getting 90 percent or 95 percent was considered a failure in their eyes," she also said.

Ninety officers have been implicated in a cheating scandal at Malmstrom Air Force Base in Montana, home to "150 missiles, providing strategic [nuclear] deterrence for the nation as the wing has continuously done since 1962 -- remaining America's 'Ace in the Hole'," according to a Malmstrom fact sheet.

James explained that the officers who cheated were incentivized to do so because those who get perfect scores are more likely to receive promotions.

"[T]heir commanders are using these test scores to be a top differentiator, if not the sole differentiator on who gets promoted," she said.

Lt. Gen. Stephen W. Wilson promised that the Air Force would change the culture in the nuclear weapons force.

"I can't stress this enough," he told reporters. "This is a grassroots level of effort. That's where the solutions are going to come from."