Overlooked in the rush to appraise Supreme Court Justice William J. Brennan Jr.'s judicial career is the dramatic impact his land-use decisions have had on real estate development and historic preservation across the United States. In a very real sense, we in the Washington area have Brennan to thank for the preservation of buildings like the Willard Hotel and the city's historic districts.

He also established a cornerstone of modern real estate law -- that local governments must take account of private property rights and pay just compensation when regulations go too far and become a "taking" -- a legal term for the possession of property.

Brennan's imprint will last long beyond his tenure on the court. In this area, for example, the downtown development district proposals pending before the D.C. Zoning Commission are likely to trigger legal challenges deeply rooted in the taking issue. So are ongoing efforts to impose severe restrictions on suburban development. Two of Brennan's land-use opinions will provide the benchmark against which judges will evaluate such challenges.

Brennan's most famous land-use opinion was the 1978 Penn Central case. This decision, sustaining historic preservation for New York City's Grand Central Terminal, was crucial not only for that building but for historic structures in Washington and in cities and towns throughout the country. At the time the Supreme Court decided Penn Central, every state and more than 500 municipalities had enacted laws to encourage or require the preservation of buildings and areas with historic importance.

In Penn Central, a developer sought to build a skyscraper above the existing terminal. The New York Landmarks Preservation Commission had rejected the proposal because of its impact on Grand Central.

Instead of submitting alternative plans to the commission, the developer filed suit, claiming that the Landmarks Commission had "taken" its property without just compensation because of the significantly diminished value of the site.

The Supreme Court upheld both the law and its application to Grand Central, providing a compelling precedent to support local laws like the District of Columbia Historic Preservation Act.

Brennan pointed to the growing recognition that too many historic structures had been destroyed without adequate consideration of either the values they represented or the possibility of preserving them in economically productive ways.

Moreover, Brennan observed, structures with special historic or architectural significance enhance the quality of life for all. He wrote, "Not only do these buildings in their workmanship represent the lessons of the past and embody precious features of our heritage, they serve as examples of quality for today."

Finally, Brennan emphasized that the developer had conceded the capacity to earn a "reasonable return" on its investment in the existing terminal. He also noted the New York law permitted the developer to transfer development rights from over the terminal to nearby parcels, thus mitigating financial burdens under the landmark designation.

Brennan recognized in the Penn Central decision that some local regulations can go too far, setting the stage for his second major land-use opinion protecting the rights of property owners from overreaching land-use controls.

In his 1981 dissent in San Diego Gas & Elec. Co. v. City of San Diego, Brennan reasoned that if a regulation becomes a taking, then the property owner is entitled to just compensation for the period of time the regulation effected the taking. In 1987, the Supreme Court formally endorsed Brennan's position in another case.

The San Diego dissent opened a new door to damage suits by property owners against local and state governments. Payment of just compensation represents a substantially greater threat to municipalities than mere invalidation of an ordinance, which had been the remedy in a number of states. City planners feared that making local governments liable to pay just compensation for regulatory taking would inhibit sound local planning actions. Brennan responded pointedly: "If a policeman must know the Constitution, then why not a planner?"

In addition to these two groundbreaking opinions, Brennan wrote 20 other land-use opinions during his service on the New Jersey and United States States Supreme Courts. In an excellent book, "Landmark Justice," Harvard Law School Professor Charles M. Haar and Jerold S. Kayden, a lawyer and city planner, write that Brennan "is unequaled for the many legal opinions he has written having profound implications for land use in the United States."

Haar and Kayden predict that either Justice Antonin Scalia or Justice John Paul Stevens is most likely to assume the mantle of the judge most active in the land-use area, with Scalia favoring private property rights and Stevens defending government actions.

In real estate, as in other areas of the law, Brennan interpreted the Constitution to make it more responsive to the needs of the people whom it was intended to protect. Like the buildings Brennan helped preserve, his judicial legacy will provide lasting benefits for both preservationists and developers.

Leonard A. Zax, an attorney, is a partner in Fried, Frank, Harris, Shriver & Jacobson and head of the real estate department in the law firm's Washington office. He is also a trustee of the D.C. Preservation League and served as co-chair of Mayor Marion Barry's Commission on Downtown Housing.