Ten years ago, when a group of local citizens got together at the Washington Hotel for the Washington Preservation Conference, preservationists and their allies in and out of government were fighting to save the towering Old Post Office Building on Pennsylvania Avenue.

They also were engaged in a difficult debate to define the ends and means of the preservation movement, which despite the noise was still on the outer edge of the local agenda.

Yesterday, as a group of local citizens gathered in the same place for the Second Washington Preservation Conference, one could not help but reflect upon the tremendous differences a decade makes. A few blocks away the Old Post Office Building, refurbished inside and out, stands as a symbol of these changes, marking a key single victory for the cause of preservation and also a vast improvement in the external status and internal sophistication of the movement.

And yet a certain disappointment, a certain hesitancy, a certain sense of doubt hung like a cloud over yesterday's proceedings (which continue this morning with sessions devoted to community views of the preservation process and "A Look to the Future").

No one can question the large advances made for preservation in the District of Columbia in the past 10 years--the saving of numerous landmark structures; the increase in the number of designated historic landmarks and districts; the vast improvement in the amount and kind of information available concerning the city's architectural past (accomplished mainly by Don't Tear It Down and its army of volunteer researchers); the continuing refinement by our better architects and developers of the relationship of new construction to the existing urban fabric; and the passage (in 1978) of a preservation law that is often said to be "the strongest in the country."

These are significant achievements; they have been of incalculable benefit to the city -- an honor to its past, a boon to its present, a promise to its future. Still, no one can afford to be sanguine about the present situation. Much has been accomplished. Much remains to be done.

Because of the 1978 law, preservation has become an integral part of the decision-making process by which the future look and feel of the city is being determined. This is indeed a transformation. Formerly the battle cry of articulate outsiders, preservation has become the hot potato very much in the thick of things. Even after four years, preservationists, planners and politicians alike seem to share a tremendous uneasiness and indecision regarding this dramatic change from outside to in.

Much of the confusion today centers upon the fate of downtown Washington. In a way this is unfortunate. One would like to have a more manageable laboratory in which to forge a new policy than the old downtown, a huge area of crucial importance to the entire region where mistakes are bound to be both highly visible and very large. On the other hand, there could hardly be a more meaningful opportunity to shape a policy that reflects a genuine "reconciliation" and "synthesis" between preservation and other equally important social and economic goals, as is often said by Mayor Barry's chief planner, James Gibson.

Gibson was one of the chief speakers at last week's meeting sponsored by the local chapter of the American Planning Association to air pro and con views of the "Recommendations for the Downtown Plan," a document compiled by the Mayor's Downtown Committee and released for comment last July. On one subject (and only one), a clear unanimity emerged: No one wanted to see the old downtown become, as practically every speaker said, "another K Street," referring to the sterile mass of built-by-zoning office buildings in the western segment of downtown Washington.

After that, there was disagreement, much of it focused on the issue of historic preservation, and defenders and critics seemed to be speaking different languages. As I considered the pertinent remarks of speakers invited to the preservation conference, the disagreement--indeed, the self-evident distrust -- that surfaced at the earlier gathering played over in my mind.

One of the main causes of the disagreement is political. Another is procedural. A third is practical. A fourth is philosophical. All are related to the vagueness, when push comes to shove, of the recommendations of the Mayor's Committee concerning the old downtown. That document, a prototypical compromise, leaves unmade almost all the really tough decisions.

The bad political vibes result mainly from the failure of the mayor to make appointments to the Joint Committee on Landmarks, and the inactivity of the city's historic preservation officer, who has yet to nominate two JCL-approved downtown historic districts (the financial district and the downtown district) to the National Register of Historic Places. Both of these steps are desperately needed if the 1978 law is to continue to function.

The procedural issues mainly involve the ambiguous status of the Joint Committee, which under the 1978 law can be replaced by a Historic Preservation Review Board appointed by the mayor and confirmed by the City Council. The confusing status of the Joint Committee, which currently serves both the District and federal governments, and/or any new board contemplated by the mayor, is compounded by a proposal from the Mayor's Committee to establish a design review board for downtown with authority over historic preservation and new construction.

These confusions are especially troubling to preservationists, who understandably see in them a significant threat to their carefully wrought handiwork. On the other side, what seems to trouble the mayor's people -- what underlines Gibson's talk of reconciliation and synthesis -- are the practical, quantitative questions concerning jobs and tax revenues.

These, too, are legitimate concerns. The hard facts concerning planning -- and acting -- on the exposed stage of the D.C. government are well known: congressional threats to home rule; a national administration that opposes interventionist planning in principle and practice; hard-ball-throwing land owners and developers who have threatened, among other things, to go to court in order to prevent the downtown historic district from becoming a reality; and the height limitation and other restrictions that limit the application of tax incentives and other trade-offs in the downtown area.

Still, one can review these facts and come to a very different conclusion, namely, that in the absence of a thoroughgoing revision of the city's zoning ordinance to couple specific land uses with specific building densities, historic preservation is the single most important, and most practical, tool available to the District government to prevent another K Street in the old downtown. In the current climate one cannot help wondering if preservation, when perceived as a threat, will not be synthesized right out of the picture.

At the APA meeting last week Betty Bird, speaking for Don't Tear It Down, quietly delivered a succinct and telling appraisal of this difference in perspective. "The Mayor's Committee," she said, "constantly addresses preservation as a problem rather than an opportunity."

And in a short talk prepared for delivery this morning at the preservation conference, Robert S. French, a philosophy professor at George Washington University, will encapsulate both the dilemma and the importance of resolving it.

"Where are we?" he asked. "We are for the moment stuck in the middle ground . . . We can't trust the 'Invisible Hand' of genuinely free enterprise because we have found the human costs to be too great. Many of us dread even more the 'Heavy Hand' of authoritarian state planning. This confronts the preservation movement with a creative opportunity . . . to help develop new processes of decision-making . . . Procedures are not a matter of indifference in a democratic society. They are not only the means for the implementation of our values; they are the implementation of our values."

The trouble is, French speaks to an audience that is reasonably willing to listen. It is the D.C. government that must be persuaded to respond to the challenge -- with imagination, vision and courage.