(CNN) -- David Hall thought that he'd been careful, working diligently in his job as an Air Force sergeant, and staying quiet about his outside life, including his sexual orientation.





Then, a female cadet went to his commander, with the revelation that Hall -- who had been first in his ROTC pilot's training class and long aspired to a military career -- was gay. Soon thereafter, in 2002, he was discharged, the life-long military brat's dreams of being a pilot suddenly dashed.





"It was stunning, disappointing," Hall said of being outed, and ousted, despite "doing everything that the Air Force had asked of me." "I lost everything that I had been working for."





But starting Tuesday, Hall's future could take another turn. That's when the U.S. Defense Department is set to formally repeal the "don't ask, don't tell" policy that has been in place since 1993.





Advocates for the change overcame intense opposition from some who claimed allowing gay men and women to serve openly would hurt the military by making other troops uncomfortable and less effective, hurting morale and the military as a whole. And it also survived a last-minute push by two of the most powerful Republicans on the House Armed Service Committee to keep the policy in place.





"There were many times when we thought it wasn't going to happen," said Brian Moulton, chief legislative counsel for the Human Rights Campaign. "(Tuesday) is a tremendous day for (gay rights advocates)."





So, too, will be the days to follow. Hall, who joined the Air Force in 1996, said he's already been in touch with a recruiter, as he's actively considering returning to the military.





"My views of the military have never changed, I've always loved the military," he said. "It is great (the law is no longer in effect), because it is going to make the military stronger."





The policy, which became known as DADT, was extremely controversial when it first took shape. During his presidential campaign, Bill Clinton had vowed to let gays fight alongside straight people. But under intense pressure from conservatives fearful that such a policy would hurt the military's effectiveness, the compromise was crafted.





Under it, military officials could not ask a soldier, sailor or airman about his or her sexual preferences. But if the troop's orientation came to light, it could lead to their discharge from the military. Some, like Hall, claim they never brought anything up themselves to their superiors, but still were forced to leave.





Since its inception, the Servicemembers Legal Defense Network -- which Hall now works for -- estimates more than 14,000 people were kicked out of the military due to "don't ask, don't tell," with the highest rates occurring in 2000 and 2001. The advocacy group said that its figures come from Defense Department statistics, obtained via Freedom of Information Act requests.





Efforts on Monday to reach several organizations that opposed the policy's repeal were unsuccessful.





But those on the other side of the debate described DADT as discriminatory.





"This is one of two remaining federal laws where the government says, in point-blank terms: Gay people are treated one way, and straight people are treated another way," said James Esseks, direction of the American Civil Liberty Union's LGBT project, adding that the other law is the Defense of Marriage Act. "Discrimination is written right into the face of law."





While serving, Hall said that it became "a game" for him and many other closeted military personnel, realizing "at work, I don't talk about my personal life." But in time, and after his discharge, the ex-Air Force sergeant said that he came to the realization that "the military was behind on this issue."





"They don't like change, and they don't want change unless they have to do it," he said.





Still, Clark Cooper,
what is being repealled In what year was the law, barring gays from serving openly in the military, enacted? Which law was enacted in 1993? What was the opinion of an ex-Air Force sergeant?
the "don't ask, don't tell" policy 1993. "don't ask, don't tell" policy behind on this issue."
question: what is being repealled, answer: the "don't ask, don't tell" policy | question: In what year was the law, barring gays from serving openly in the military, enacted?, answer: 1993. | question: Which law was enacted in 1993?, answer: "don't ask, don't tell" policy | question: What was the opinion of an ex-Air Force sergeant?, answer: behind on this issue."