The Post is incorrect in stating that development in Fairfax County is "done or in the making" {editorial, July 9}. Many decisions about the level and pace of development remain to be made. We are looking at a county that, it is predicted, will have 300,000 to 400,000 more people over the next generation.

It is imperative, as Audrey Moore has argued during her 16 years on the county board, that remaining development be carried out in a rational fashion. Fairfax County must and will continue to grow, but if it does so in a haphazard fashion without regard to consequences for the quality of life, citizen and voter discontent will mushroom. At worst, we may see the voter backlash that has produced horrendous antigrowth policies in the San Diego and San Francisco areas.

The Post is also in error in likening the platforms of the two candidates. Mrs. Moore represents orderly growth dependent on the ability of local governments -- working with the private sector -- to provide transportation and other services. She is pledged to join with citizens and the business community to achieve continued prosperity and an excellent quality of life for all residents. Jack Herrity, on the other hand, has never met a building he doesn't like and believes enough concrete ribbons will solve all problems.

All who complain about "Tweedledee and Tweedledum" politics should be thrilled by this race, where the candidates are enunciating distinctly different visions of how to move into the 21st century. What The Post should recognize -- and applaud -- is that all of us, as democrats with a small "d," have an opportunity to make a clear choice at the polls.

HARRIS N. MILLER Chairman, Fairfax County Democratic Committee Falls Church