The Montgomery County Council's public hearings on Silver Spring development were a remarkable demonstration of citizen activism. A series of reasonable, well-informed and committed speakers dramatically exposed a potential catastrophe in their community.

They revealed County Executive Sidney Kramer's proposal to amend the Silver Spring Sector Plan as a sham. No more can the advocates of concrete-jungle development claim it will benefit Silver Spring; no more can they deny that their plans are a perversion of the planning process.

Those plans sacrifice the long-sought mix of retail and residential development to the sterile monotony of office buildings; they obliterate the principle that growth must be linked to the traffic that can reasonably accommodate it; and, most certainly of all, they demonstrate that the Kramer plan runs counter to the aspirations of the Silver Spring-Takoma Park community, which must live with it.

Whatever the final outcome of this debate, one fact is clear: the people have rejected the executive's power play. "Voted for Sid, sorry I did" may just be a bumper sticker now, but it also may be an omen of the political future of Montgomery County.

The focus is now on the county council, which will ignore the citizenry at its own peril. Rarely has a grass-roots movement spread as deeply and quickly as that opposing the Kramer plan. That movement will not be denied and it will not have to look far for evidence of the council's heed: the profile of Silver Spring will cast a shadow for many elections to come. MICHAEL R. VERNETTI Silver Spring