On weekday evenings, after the government office buildings on the Mall close for the night, the R.S.V.P. restaurant and lounge in the Waterside Mall in Southwest Washington picks up a steady stream of customers. They are mostly black and mostly entering the middle class, with comfortable incomes and life styles, thanks to the inviolable government presence here that has been the path to modest affluence for generations of black Washingtonians.

Jack Styles, a 30-year-old transportation analyst with the Washington Council of Governments, could be considered typical of the kind of young black Washington just ready to break into the middle class, and who has found life relatively secure in this city whose principal industry is government.

His group is distinct from the more established Washington black middle class. His group prefers the urban-renowed Southwest to Northwest's more affluent upper-16th Street or the older-line Ward 5 area of Northeast. They are more likely to be found here in the mirrored, disco decor of R.S.V.P. -- the slicker, more chic counterpart of Faces, the other popular black middle-class watering hole on Georgia Avenue.

But both groups have one thing in common -- they have been able to establish some degree of economic security as the beneficiaries of government.

Like Styles, many black Washingtonians now reaching age 30 have enjoyed the good life, bouncing from colleges where they received government funds into solid government jobs. Others used the antipoverty programs and community agencies as their springboards into middle-class affluence. Some became the beneficiaries of then-budding affirmative action programs in the private sector. Many others went on to become consultants, relying primarily on the federal and local governments for contracts.

Now, for the first time since the heyday of the 1960s and 1970s, this group of young, up-and-coming blacks is being threatened like never before. Ronald Reagans pledge to trim back the size of government and its programs -- and even Mayor Marion Barry's newly professed fiscal conservatism -- are cutting deeply against young blacks like Styles, who are just now at the edge of middle-class incomes. And, like Styles, many now are being forced to consider for the first time what life may be like without the government as their principal provider.

Styles, a Washington native, comes from a middle-class home on Varnum Street NW, on the edge of the Gold Coast, from parents who both work for the government. His mother was a mental health counselor at D.C. General Hospital, and his father was an officer with the Executive Protective Service. "In some way, shape or form, whole generations have worked for the government," Styles said, sitting at one of the counter bars in R.S.V.P., formerly W.H. Bone under its previous ownership.

"A lot of people in this town have done well by working for the government," Styles said. "When I was 13, I worked in the State Department part time. That was it. You got out of school and went to work for the government. Everybody you knew in the black community either worked for the Post Office (or) the UPO," the United Planning Organization, the city's community action agency.

In all his years in Washington, Styles said, he has never been independent of the government, its programs or the surrounding commmunity advocacy groups. He went from Roosevelt High School in Northwest into the old Federal City College on a work-study program. He caught the tail end of the civil rights movement. In the early 1970s, when the city was first breaking ground to construct its Metro subway system, Styles, who had studied electrical engineering, was a valued commodity for contractors looking for qualified blacks.

"You could float back then," he said. "Living was easy back then. Go to school, get into a work-study program. It was easy, if you took advantage of the situation.You could come in through a government program and work for the government."

"Very few ventured into other things," Styles said. "Very few of us are really free of the government. That is my goal now, to break free. It's too bad most of us are dependent on our government jobs. I am. I'm comfortable where I am. But if I get cut, I guess I'll just have to go out and beat the pavement."

"The black people in this town kept the country moving," Styles said, "because we moved all the paper. Now black folks are going to have to learn to adapt. And that," Styles said, "can make you hostile to any kind of cuts. My whole burn, my yearning in life, is to be free."