Lessons from a D.C. dropout; Running and Fighting: Working in Washington, by Brett Fromson. New York: Simon & Schuster. 160 pp. $12.95.

''I had come to Washington as a liberal, an optimist. This town was turning me into a conservative, a pessimist . . . . I was in no position to change the situation. That had to come from the top.''

Shades of a disillusioned government worker caught up in the floodtides of Watergate? No. Brett Fromson came charging out of Stanford in the mid-1970 s--clutching an economics degree and hopes of being a mover and shaker for the public good.

Within a year, his bubble burst. A major study he had fashioned for the Joint Economic Committee of Congress was suppressed for political reasons. Fromson was so appalled, he ended up leaking it to the press. And, not surprisingly, that was his undoing. He was ostracized by his colleagues, assigned to menial, meaningless tasks, and ultimately driven from his job.

Fromson warns young people seeking government careers that their ideals are likely to be squashed. But he allows that ''just because I didn't fit in'' doesn't mean others won't.

Actually, the author's side themes are the most revealing part of his work. We would like to know more about his ''best and brightest'' young roommates--Nicholas, the lobbyist and son of a former ambassador; Charity, the congressional aide and daughter of a well-to-do family; and Joni, his constant girlfriend who tagged along from Stanford.

The book is offered as nonfiction. But all the politicians' names are changed. There is even a flimsy scenario about a friend who turns out to be a Soviet spy or a son-of-a-spy, or a probable spy, or something.

But the case Fromson makes is not flimsy: that too often private, personal, political interests entirely dwarf public interest. Is it too naive to believe that there are those working at all levels of government who refuse to accept this as business-as-usual?