By any measure, 1990 was a terrible year for Mayor Marion Barry. It began with his videotaped arrest in a drug sting, and saw him convicted of cocaine possession and defeated for a lesser office. And in the end, his wife moved out on him.

Barry, once one of the nation's most prominent and promising black politicians, is set to leave office on Jan. 2 unemployed and with a six-month jail sentence hanging over his head.But the former civil rights worker, who has relished the underdog's role in a 30-year career in the public eye, insists his chin is up - even after being forced to abandon plans to run for a fourth, four-year term and suffering a humiliating defeat in his bid instead for a city council seat.

"Some people would be sad, other people would be disappointed . . . sort of downcast," Barry said in an interview. "I feel relieved. Some people would feel regret, but that's not here with me - maybe it ought to be, but it's not."

But detractors and supporters alike can't help but wonder at the promising future once held by a man who left behind the bleak poverty of his boyhood in Itta Bena, Miss., to become a foot soldier in the civil rights movement and later the unrivaled star of Washington's local politics.

"He had his life together beautifully at one time, but he's blown it, and he blew it in this last term," said Max Berry, a former Barry supporter who directed the mayor's 1986 re-election effort. "He did a lot of good things in those first seven years that no one will remember, and he's the reason that his own life is in disarray."

Longtime supporter Calvin Rolark, a local community activist, said Barry is "a success story, because he showed what true black leadership can be about."

"At the same time, he showed the effect of drugs on individuals, no matter how strong people are," Rolark said. "I think the history of Marion Barry will show that you can go from a law maker to a law breaker."

Dissident black Roman Catholic priest George Stallings described Barry's legal travails as "a national tragedy," but insisted that the mayor should be remembered for his wide range of accomplishments, particularly the development of a minority contracting procedure that generates more than $600 million annually for businesses owned by African-Americans, Hispanics and other groups.

"On that front, Marion Barry took the city to a new level, and that was a great example to other municipalities," Stallings said. "He was a very strong leader, and that should not be forgotten either."

Barry was both relaxed and reflective as he prepared to leave the job he has held for a dozen years, but he demonstrated none of the braggadocio that used to be his trademark. The mayor, who has admitted to alcoholism, addiction to prescription drugs and occasional cocaine use, credits his recovery program with taking the blunt edges off his personality.

"This isn't like death," Barry said of his departure from the local political scene. "I've gotten ready for this, and I look back and say, `Someone's going to take over.I won't have that awesome responsibility anymore,' and in some ways that is nice. I have more perspective now."

Barry stressed his contributions to the city, including his minority contracting plan, a downtown development boom, senior citizen and youth programs, and the order he initially brought to the city's chaotic financial books. But he admits that in recalling his career, many will think first of his legal troubles.

"I believe that in time, my personal situation will evaporate from people's minds and they will finally get around to the good things I did here," Barry said. "But that's what people will remember for awhile, and you can't stop that."