Northeast of Cleveland, near the southern shore of Lake Erie, stands the town of Euclid, Ohio. Like New York, Washington and other American municipalities, Euclid had adopted a zoning ordinance in the 1920s and attempted to enforce it.

A local landowner, frustrated because regulations prevented his residentially zoned property from being used for commercial purposes, sued the municipality. In Village of Euclid v. Ambler Realty Company, Ambler sought to have Euclid's zoning ordinance declared unconstitutional on the grounds that it was an unreasonable exercise of government's police power.

The claim was that zoning amounted to a de facto taking of property without due process of law. It was confiscatory, Ambler asserted, depriving land of its value and its owners of rights and liberties guaranteed by the Constitution.

Euclid insisted that zoning was a legitimate use of police power to prohibit potential nuisances, even if they did not yet exist. The town argued that the public interest took precedence over private interests. Protection of public health, safety, welfare and morals -- the police power specifically granted to government by the Constitution -- justified zoning, Euclid said.

The right of government to exercise its constitutionally mandated police power was the preferred basis for zoning, of course. If property values fell because of a zoning action, affected owners did not have to be compensated. By contrast, when government takes land through its power of eminent domain, it must compensate owners fairly for such losses.

The case went to the Supreme Court, with every zoned and unzoned community and city in America watching. The stakes were high. If Ambler prevailed, then no zoning ordinance in the country would be legal. Further, because the legal issues under consideration were broad, rather than narrow, a pro-Ambler decision effectively would preclude any future zoning ordinance from being enacted and enforced anywhere.

In 1926, the Supreme Court ruled in favor of Euclid. Zoning was declared to be a legitimate use of the police power of government so long as it was reasonable, nondiscriminatory and nonconfiscatory. The court recognized that zoning regulation could be abusive. But it said that, only in individual cases, where specific circumstances supported such contentions of abuse, could zoning be overturned.

Recall that zoning ordinances really prescribe more than allowable land uses -- residential, commercial, industrial or otherwise. They also regulate the intensity of use by setting limits on lot sizes, lot coverage, yard sizes and setbacks, residential density (sometimes expressed as numbers of dwellings per acre), and building height and size.

Allowable building size, or bulk, often is stated as the ratio between the building floor area (the total of all floors above grade) permitted on a lot and the lot area. It is commonly referred to as the FAR, the floor area ratio. For example, in a zone where an FAR of 10 is permitted, 1,000 square feet of building floor area can be constructed for each 100 square feet of lot area. FAR allowed in a given zone is clearly a major determinant of both architectural form and economic value.

After the landmark Euclid decision, cities, towns and counties in every state proceeded to write and adopt similar zoning ordinances. In fact, to this day, most such ordinances are referred to as examples of Euclidean zoning (not to be confused with Euclidean geometry), reflecting the 1926 legal event that made it all possible and sustainable.

Traditional Euclidean zoning ordinances have three components: 1) a list of definitions considered necessary to make clear the exact legal meaning of words such as "one-family dwelling," "front yard," "floor area," "lot width," "alley" or "light industry"; 2) written regulations describing each zoning category with its allowable uses and limitations on physical development; and 3) a zoning map dividing the jurisdiction into various land-use zones governed by the written regulations.

Those charged with drafting zoning ordinances faced inevitable conflicts. Most cities, like Washington, already had well-established patterns of development and land use prior to adoption of zoning. Thus, zoning maps and regulations had to take into account and largely follow such existing patterns. In this regard, much early zoning was destined initially to reinforce, rather than direct, urban land-use patterns.

Yet zoning clearly would influence future growth and real estate investment returns. Owners of property who thought that someone might enrich them one day by purchasing their land for an office building or commercial center suddenly found themselves owning land indelibly marked for row houses, or less.

Many zoning ordinances were drawn up by attorneys, surveyors and civil engineers, not by architects or urban designers. Therefore, zoning laws and maps rarely embodied concepts for the conscious, comprehensive shaping of urban form, city silhouette, streetscape, transportation and other patterns of use with three-dimensional, visual implications.

Zoning was mostly a two-dimensional mapping exercise determined by previous usage, demographic growth predictions of questionable reliability and, not incidentally, current and potential real estate values. Moreover, the fundamental policy assumption characterizing all Euclidean zoning in the United States was that homogeneity (of use, of economic and social levels, of building type and quality) was always desirable. All things being equal, the status quo was to be preserved.

Even ardent supporters of zoning worried about its inflexibility, about its dependence on fixed boundaries and codified constraints. People on all sides realized that circumstances change over time, that tomorrow's goals and values differ from today's just as today's differ from yesterday's. They also recognized that, in specific cases, conditions could justify departing from strict application of current standards.

Therefore, zoning ordinances typically contain provisions for three kinds of departure or change: 1) the "variance," a form of administrative relief, minor in nature, from some particular requirement of the regulations whose enforcement would constitute a hardship for the owner (for example, a slight variation in a setback dimension might be allowed); 2) the "exception," usually an additional use allowed under special circumstances (such as a private school or a nursing home in a residential zone); and 3) the zoning map amendment, the most radical change, through which a specific property or area becomes reclassified or rezoned for new uses not previously permitted.

None of these changes can be effectuated routinely. The District and other jurisdictions have zoning boards appointed by mayors and/or legislative councils. Boards are empowered to hear formal requests or petitions for variances, exceptions and rezonings in accordance with articulated procedures and evaluative criteria. Most procedures involve public hearings and also require that zoning agency staffs prepare reports and recommendations for action by the zoning board.

Despite these protocols for flexibility, there is a natural tendency for owners and developers to undertake improvements fully in conformance with existing regulations ("matter-of-right" development). This saves time, avoids public exposure and controversy, and minimizes risk and expense. But it may not result in the most appropriate use of the property. And it may not reflect the property's potential fair market value or represent the best interests of the public.

Over the last 60 years, developers and governments have come to recognize that zoning could do more than just protect the status quo or impose burdensome restrictions. It could be a tool for city building, a catalyst -- rather than a deterrent -- for innovation in design and development. Private and public interests do not always have to be at odds.

NEXT: Zoning, economics and aesthetics