Marilyn Piety remembers well the lengthy battles her civic association waged in the 1960s and 1970s against development proposals for land near Flower Avenue. Finding it wearing to fight constantly as the opposition, the group later decided to work for a project, and the result was the opening of a neighborhood library.

That success a decade ago taught Piety that "it's better to work for what you want," a lesson she thinks should be applied to the present battle over the future of downtown Silver Spring.

What Piety wants -- what she thinks most residents want for downtown -- is a thriving community with viable stores.

Toward that end, Piety is an outspoken and fearless supporter of developer Lloyd Moore's plan for shops, offices and hotel rooms.

For the veteran of civic associations and political campaigns who now works in the county's budget office, the new role has surprised her onetime adversaries in business and government circles and angered some of her colleagues in the civic movement.

Turncoat and sellout charges have been hurled at Piety, and she said she has lost the companionship of some people she had thought of as friends.

"It hurts . . . . It feels lonely, very lonely," Piety said. "I don't have any other choice but to hold to my principles even though they are unpopular in some quarters."

Piety, stating for the record that she has no financial or other kind of stake in any redevelopment plan, said her views on downtown are the result of many years of impartial study.

She points, for example, to the Art Deco-style shopping center and theater that Moore proposes to demolish but that some scholars say are architecturally significant and worth preserving. In 1984, the Allied Civic Group, a coalition headed by Piety of local civic associations, endorsed creation of a historical district in downtown Silver Spring, favoring the preservation of historic buildings and making new development compatible.

Piety said she did not want the buildings destroyed until studies could be made, and her reading of subsequent analysis convinced her that historic preservation is not economically feasible. "It is just not in the cards, so the question is, 'What next do I want for Silver Spring and how do I get it?' " she said.

Because retail space is critical to community aims and because Moore has proposed including retail shops in his project, the county and its citizens should be working with him to make the project a reality, she argued. "You know you don't always have an unlimited number of choices," she said. " . . . Sometimes if you say no to something, you can get something that is worse than, not better, than what you rejected."

Piety's fear is that stiff citizen opposition will place Moore in a position where it is economically easier for him to build a project that is just office space -- the very thing the citizens say they don't want.

"He is going to build the office space; there is no question about that," she said. "The retail is the extra component, the bargain, and the retail is what we could lose."

Piety also said she likes Moore's proposal. She said she does not think it is at all massive, a criticism made by some opponents; and to the concern that increased traffic will cause gridlock in neighborhoods, Piety expressed confidence in county plans for handling increased traffic. Besides, she said, she lives and drives in Silver Spring all the time and shebelieves that traffic isn't that bad at the moment.

Piety, a former public relations executive who decided a year ago at the age of 50 that she wanted a career change, said she is distressed that the debate has become so personalized. While conceding that Moore's plan is at issue, Piety said the questions before the council concern the number of jobs that can adequately be added and it is a concern that affects a lot of developers.

Piety, an early Sidney Kramer supporter in last year's county executive race, noted that both the executive and the planning board -- independently and based on their own studies -- have recommended 13,500 additional jobs for Silver Spring. The planning board has passed on that recommendation to the County Council while expressing some concerns.

Let the council debate that number, Piety said. "I think they will have a hard time coming up with another number. And let's get on with the business of working constructively for what we want."