To walk the streets of downtown Washington today is to be saturated with the sights and sounds of destruction and construction. It's messy, noisy, incessant, disturbing, amazing.

Entire blocks of buildings have been boarded up, awaiting the wrecking ball. Other blocks have been completely rebuilt in a new image, all signs of previous occupants extinguished. Familiar buildings have become surreal facades, propped up with great steel armatures. The area is pocked with excavations. Towering cranes are almost everywhere. The scene changes from week to week, day to day.

This is the "old" downtown, the one everybody used to go to when it was the true center of the regional economy. Its rebuilding is about halfway done, according to planners and developers who set the process in motion more than a decade ago. When the process is completed, in 10 years or so, the old place will be unrecognizable.

For this reason, among others, the city government, the business community, housing advocates, preservationists, churches and other citizens groups have been engaged for about a year in a difficult, divisive fight over downtown's future. The focus of the struggle in recent months has been the five-member Zoning Commission, an appointed body with significant, though limited, power to establish the basic rules of the development game.

After an arduous series of hearings lasting through the spring, the commission surprised all concerned last month by tentatively deciding on a dramatic mid-course correction in the rules, establishing important new provisions for residential, retail and arts uses downtown and key new protections for historic buildings. If the decision holds -- the commission meets next week to vote officially -- it would throw the entire issue of downtown development back to the mayor and city council during an election year.

It could be argued, of course, that the old downtown already is gone. Long before the current cycle of building started, regional demographics had begun to change, and with them patterns of travel and land use. Washington's real estate money moved elsewhere, erecting a large new stock of office buildings west of 15th Street NW, the old downtown's western edge. (For planning purposes, it should be noted, downtown's borders are elastic, extending north and east from Pennsylvania Avenue and 15th Street, respectively, to M Street and Third Street.) Suburbs continued to expand and to change. Immense new clusters of stores and offices were developed for this mobile and largely affluent market, successfully challenging downtown's preeminence as a place to shop, work and play.

Downtown responded sluggishly at first, although the completion of the Convention Center in 1982 was a tangible sign of a long-planned new direction. But the process of assembling the land for potential projects went on inexorably, and land prices continued to rise as speculators bought and sold parcels among themselves. In the mid-'80s office construction really took off.

Clearly there are gains to the city from this remarkable rebuilding enterprise. Besides representing a vote of confidence in downtown on the part of developers and prestigious white-collar firms, the new offices add importantly to the municipal tax base and offer lots of new job opportunities. There have been isolated cases of increased retail activity -- the doubling of the number of Chinatown restaurants being a chief example. And as a whole there has been a gain in architectural quality, when these new buildings are compared with those erected a couple of decades ago on and around western K Street.

If the center did not hold, neither did it decay as drastically as often has been claimed. Though physically the worse for wear, many downtown buildings large and small continued up until quite recently to house offices, residences and a variety of interesting trades and stores -- the area possessed the quirky sort of vitality peculiar to districts just holding on or in transition. And for all of its problems through the 1970s and much of the 1980s, the old downtown retained a distinctive architectural character and remained one of the few places in the metropolitan area where different races and classes of people rubbed shoulders on a daily basis.

By now the appearance and shape of the new downtown already is apparent through the construction dust. It is a place to be made up largely of super-blocks, or super-half-blocks. The new buildings are bigger in both horizontal and vertical dimensions than those they replace. Often they're connected via interior passageways. Many have enormous sky-lighted atriums. Except for Chinatown there has been a general decline in small-scale retail activity, in part because these buildings were not designed with stores in mind.

Some of these buildings are handsomer, more subtle and more satisfying than others, but unquestionably the size and interior focus of the new structures greatly alter downtown's character. Though duplicated by responsive architects in several of the new projects, the old staccato street frontages, with appealing changes in scale, period, style, materials, textures and colors, are fast becoming relics. In many ways the pattern of the new buildings and the territory they define are perfect expressions of a "rational" city, a technocratic dream of a clean, well-ordered white-collar workplace absent the sorts of diverse activities one customarily associates with city centers.

The realization that the operations of the private real estate market, left unchecked, would by the year 2000 just about eradicate the old downtown with more of the same is the most important reason for the new urgency in the downtown debate. One good look at this future is enough to turn some folks off.

This conflict has a history, of course. The library shelves of downtown veterans are by now overstuffed. A critical turn arrived in the early '80s when D.C. Mayor Marion Barry appointed a broad-based committee to assess downtown's prospects and come up with a consensus vision. The panel's key recommendations, published in a sleek 1981 document, "A Living Downtown for Washington," were incorporated in the downtown element of the city's comprehensive plan, adopted by the D.C. Council in 1984.

Even then, however, thoughtful observers were aware that without important changes in the high-density commercial zones covering much of the downtown, the proposals for housing, preservation and a stimulating mix of retail, entertainment and arts uses would remain little more than a list of nice wishes.

Throughout 1989 the city's understaffed Office of Planning labored in secret to come up with a proposal to ensure that the comprehensive plan goals for downtown would be met without unduly upsetting the downtown development community, made up of developers, financial interests and their high-powered lawyers. What it produced, after a false start or two, was an ambitious and immensely complicated overhaul of the zoning regulations called the Downtown Development District. Citizens groups, alarmed by what they saw as excessive bonuses granted to office builders by the city's plan, countered with their own proposals.

Consequently, when the Zoning Commission began its series of hearings in February, three proposals were on the table: the city's, a radically contrasting plan put forward by a small but resourceful planning group called the Coalition for a Living Downtown, and a plan to reduce permissible densities in the Downtown Historic District forwarded by the D.C. Preservation League.

That the commission consented even to listen to the alternative plans was something of a disappointment for the development community, which had strongly advocated confining the hearings to a consideration of the city's plan. Ironically, it is a plan developers and their allies richly despise. Neil Bien, testifying for the Board of Trade, summed up their position by dismissing the objectives of the Downtown Development District as "unrealistic, unachievable and unnecessary."

Basically, the plan is an attempt to harness the mighty engine of office development to attain certain stated social goals, a not uncommon strategy that has had success in other redeveloping downtowns. But despite its good intentions, the plan's sizable flaws were revealed during the hearings.

Practically everybody who joined the parade to the witness table agreed that the city plan is much too technical and too complicated -- even its authors would concede the point on occasion. Developers correctly pointed out that the complex zones designed to stimulate "preferred uses" (housing etc.) often overlapped, creating both bureaucratic and financial nightmares. And advocates for the alternative plans probably were right to fear that this very complexity would offer endless opportunities for negotiated exceptions detrimental to the plan's goals.

Parties on all sides of the issue also were justifiably impatient with the city government for sending out thoroughly contrary signals -- on the one hand offering this plan to implement a "living downtown," and on the other exempting certain crucial city-owned properties from its own regulations.

The most important of these is the four-block parcel of land north of Massachusetts Avenue, opposite Mount Vernon Square, which was cleared long ago for the downtown campus of the University of the District of Columbia. This splendid site, the southern terminus of the Shaw neighborhood, is critical to the notion of a close-in residential quarter, and yet the city foresees a megastructure there, with a new convention center, university buildings, offices and hotels (plus a token few residences). Excepting the university, such intense uses are inherently at odds with the surrounding neighborhood and with the letter and the spirit of the city's own plan.

Exactly the same can be said of the city's announced intentions to demand very little or no residential uses on the huge Far East Trade Center site in Chinatown, the Gallery Place site on Seventh Street and the Employment Security building site on Pennsylvania Avenue at Sixth Street NW. Such inconsistency inspires minimum confidence, and maximum cynicism, concerning the city government's ability and will to follow through with its ostensible downtown policies.

Another serious defect is the plan's overreliance on a single tool -- bonus office densities -- to achieve its ends. A developer meeting the target for a highly prized arts use, for instance, would be permitted to build extra office space at a 3-to-1 ratio. Similarly, the developer meeting the residential requirement in a high-density commercial zone south of Massachusetts Avenue would be awarded additional space at a 2-to-1 ratio. Some of the bonus space could be built on the site, and some in designated "receiving zones" elsewhere. (The latter process is called "transfer of development rights," or "TDRs" in the parlance.)

Developers are suspicious of the highly speculative TDRs, and rightfully so. Volume trading of such development "futures" is neither a very tidy nor an appealing way to do business -- plowing through the transcript with its repetitious invocations of TDRs at times seemed perilously akin to reading "Dead Souls," the satirical Russian novel in which the protagonist makes trade in deceased serfs.

The amounts of space are far from negligible. George Colyer, a planner and member of the citizens coalition, noted that if systematically carried out the city plan would produce more than a Pentagon of TDRs -- 4.8 million square feet to be precise -- that might land on some unsuspecting section of the city. This in addition to the 5.7 million square feet of bonus office space the plan would allow in the downtown district itself. In effect, Colyer said, "It's a major up-zoning." With figures such as these, one wonders why the developers seemed so outraged by the city plan.

One reason clearly is economic. "The commercial real estate market and the housing market operate under distinctly different sets of principles," observed Wiley Williams, deputy mayor for economic development. Developer Ellen Sigal noted that although it costs 10 percent more to construct housing than office space, income from housing is less. Downtown office buildings bring in up to $45 per square foot, she said, while downtown residential properties can expect a return of about $20 per square foot.

Sigal, who co-chaired the Mayor's Commission on Downtown Housing, protested that the city's promised bonuses are insufficient to ensure that the residential units actually get built. That panel recommended a much more sophisticated package of incentives, including tax abatements, some TDRs, a housing bond issue, subsidies for affordable housing and a powerful public-private Downtown Housing Development Corp. The net cost to the city of this $150 million program was estimated to be about $10 million.

Another reason to suspect that the city's plan would not meet its downtown housing targets is the provision of "in lieu" contributions by developers to a citywide housing fund. With justification, critics see this as a loophole by which developers can "buy out" of the downtown housing obligation. Others, however, see it as a means to attack the problem of affordable housing in a city seriously strapped for federal and local housing funds.

Potentially, this is a deeply divisive issue, and one particularly subject to inflamed oversimplification. The downtown housing proposal, said a spokesman for the Coalition for Non-Profit Housing Developments, is a "giant incinerator that will have the effect of further destroying the lives of the poor and devastated neighborhoods in this city." The tentative alliance between downtown developers and neighborhood housing activists offers convincing proof that the old downtown, which has been losing residential population for two decades, no longer has a major constituency of its own.

In the long term, however, a vital downtown is in the best interests of the whole city and, arguably, the entire metropolitan area. A majority of the Zoning Commission appears to have recognized this in a straw vote last month, which endorsed certain sensible aspects of the city's proposal while attacking its major flaws.

Although many important details won't be known until next week's final vote is taken, published and carefully studied, the lineaments of the informal decision, based upon a memo circulated by Chairman Tersh Boasberg, seem judicious, even statesmanlike. An "overarching goal" was established to "create a vibrant downtown of mixed uses: offices, retail, hotels, theaters, museums, historic buildings and neighborhoods with significant housing opportunities."

Such words have been uttered to the point of cliche. For once, however, they are backed up with substance. Boasberg's memo highlighted the need to "consider all available sites" in order to meet the goal, thereby setting the city government on notice that it too must accept the medicine it prescribes for others.

This decision alone would be cause for celebration, and there is more. The commission also seems ready to insist that a certain amount of residential construction be mandated in the north-south Seventh Street corridor linking the Mount Vernon Square area to Pennsylvania Avenue, thus attempting to ensure that the new residential neighborhood there (developed under mandate by the Pennsylvania Avenue Development Corp.) will not be just an isolated enclave.

In addition, acknowledging the political pressures (and recognizing the fairness of some of the arguments behind them), the commission embraced the idea that a portion -- reportedly 25 percent -- of the downtown housing goal should be built "off site," in the city's needier neighborhoods. For historic preservation, the commission apparently bit the bullet on the down-zoning necessary to protect the few remaining stretches of downtown's 19th-century streetscape from incompatible development.

Perhaps most importantly, the commission would appear to be prepared simply to do away with the city's plan to give office bonuses in exchange for housing. This is drastic medicine, indeed, but it deflates the bubble of unbelievability that the city's plan could never escape. The Zoning Commission is to be congratulated for its courage and clearheadedness, and urged to maintain course.

The development community is complaining that it won't work, and, without further public action, it won't. But the responsibility now shifts definitively back to the city government and its elected officials, who will have to grapple in earnest with the challenge of shaping public policies to achieve the oft-stated goal of a "living downtown." It's a lot to ask, true, but hardly too much. The downtown of old will not return, but we've a right to expect a better new downtown than, so far, we've been getting.