The proposed masterplan for the development of the Capitol complex is surprisingly good news.

It is sensible and sensitive. With one exception. It does not annex territory or displace people. The exception is acceptable.

This is in contrast to the arrogance of congressional expansion in the 1950s and 60s at the expense of the Capitol Hill community, which was, at the time beginning to emerge as one of the most charming neighborhoods in the country.

Suspicion of the edifice comlex of Congress and its architect of the Capitol still lingers in view of the needless extension of the east front of the Capitol, the Sam Rayburn House Office Building, with its endless, pompous marble corridors; the oppressive James Madison Library, which displaced four blocks of charming Victorian townhouses; and the constant threat of further, uncontestable annexations. In January 1963, the assistant architect of the Capitol, Mario E. Campioli, stated that "every effort should be made . . . to extend the Mall to the east from the Capitol to the Anacostia River" and line it, four blocks deep, with massive marble monuments and Rayburn Buildings.

The new master plan was prepared by a new architect of the Capitol, George M. White, and a remarkable team of consultants. It is now going to the printer and will be submitted to Congress next January for public hearings and approval.

It charts growth for the next 50 to 75 years and is a logical sequel to the L'Enfant Plan of 1792, which located the Capitol in relation to the rest of the Federal City, and the McMillan Plan of 1902, which accommodated the inevitable growth of government.

Like the McMillan plan, the new master plan, ordered by Congress four years ago, does not specify the extent or nature of that growth. It merely says: "If Congress needs new buildings, here is where they should be."

As White's executive assistant, Elliott Carroll, pointed out, the McMillan plan in 1902 called for 75 new buildings, but only 38 of them have actually been built.

In sum, the new masterplan provides for adding roughly five million square feet of new office space to the existing 9.3 million. Some of these buildings, less massive than the present ones, would be built on what are now parking lots, as surface parking would gradually be eliminated in favor of underground garages and improved public transportation. Some additional space would be provided within the large inner courts of old ones (enhanced by intensive planting as in the courtyard of the Ford Foundation Building in New York). And some new buildings are proposed for mostly vacant sites south of the Rayburn Building.

One, southwest of Canal Street, is now owned by the city's Redevelopment Land Agency. Another, between Ivy Street and New Jersey Avenue, belongs to developer Oliver Carr. Buildings here can only improve the unsightly mess the freeway spaghetti, railroad tracks and defiant non-planning have made of the southern approach to the Capitol.

The only possible objection to these proposed office construction sites is that one of them, along New Jersey Avenue, could endanger a row of handsome townhouses. But, as Elliott Carroll suggests, the new office could easily be built behind the old houses, as was done on Lafayette Square. Besides, nothing may happen for 50 or 75 years.

What is happening now is that Congress is shown a more compact, more urban arrangement of buildings that with due and generous landscaping, is entirely in the prevailing Beaux Arts tradition. The plan calls for two hard, paved plazas in the style of the great squares of Siena. But all in all, the proposed agglomeration of buildings is far softer, far more open than the Federal Triangle down the hill from it.

Congress will also be shown how beautiful and serene the Capitol complex could be if the blight of parked combustion engines were removed. The master plan provides working space for 40,000 people on the Hill, double the present number. But it would increase the present 10,000 parking spaces only slightly, in hopes that at least 40 percent of the workers will use public transportation. A shuttle-bus between Union Station and Capitol South Metro stations is proposed immediately. In the long run, this would be replaced by an underground shuttle similar to the one between Grand Central Station and Times Square in New York City.

All this appears not only practical but also essential and entirely in keeping with the historic development of the Capitol and the city.

The most important aspect of the plan may be the exemplary method by which it was drawn. The McMillan Plan, designed by architects Daniel Burnham and Charles Follen McKim, landscape architect Frederick Law Olmsted Jr. and sculptor Augustus Saint-Gaudens, under the aegis of Sen. James McMillan of Michigan, sought to make the finest plan they could conceive. They decided it could be compromised later, if necessary.

The 1980 plan follows no architectural fantasies, but is drawn to meet the "environmental capacity" of the area and the needs and wishes of the people in and around it.

The "environmental capacity" gives the planners the maximum amount of new construction possible if due consideration is given to historic preservation, the socioeconomic consequences, traffic congestion, the capability of the utilities, relocation of residents, noise, vegetation, wildlife and the water supply.In other words, the planners -- to my knowledge for the first time in any effort to accommodate urban growth -- determined first just how much the environment ecology could take.

Next, they listened to what people were willing to take.In more than 50 meetings, Carroll and his group presented preliminary plans to the residents of Capitol Hill, the city, the region and -- through selected representatives, such as environmentalist Rene Dubos and political scientist Richard Scammon -- the nation. The wishes of all these groups concerning historic continuity, land use, transportation and esthetic impact were deemed reasonable and made part of the plan.

The basic plan was drawn up by White's staff with the help of urban designer David A. Wallace, landscape architect Ian McHarg, economic planner Philip Hammer, transportation planners Alan M. Voorhees, Inc., historian Frederick Gutheim, and architect Romaldo Giurgola and their firms. It was then reviewed by three of the nation's most prominent designers, architects I.M. Pei (who designed the East Building of the National Gallery); Harry Weese (who designed our Metro stations) and landscape architect Hideo Sassake (who designed public spaces all over America and served on Washington's Fine Arts Commission).

Each of them took the drawings home and worked them over for a month. It will be hard to argue with the result. Problems and controversies are not likely to result from the long-awaited master plan, but from its implementation.

In the first place, the plan only prescribes the location of buildings, not their function. It provides only an "envelope," as planners call it, not what is put inside, or even what it should look like.

We are witnessing a revolution in office work wrought by computers and other electronic gadgets that will surely affect the workings of congressional offices, research and management, as it has newspapers and businesses. It will also, before long, affect the spaces in which office work is performed. But office automation -- the "black box," Carroll called it -- is the exclusive reserve of the Senate Rules Committee. The planners are not supposed to consider it. This may prove to be a mistake.

The new master plan does prescribe some design objectives, all of them laudable. One calls for maintaining and improving Olmsted's marvelous landscape design. Another would give a more determined look to the Union Station Plaza -- in part by adding a building to the east of Burnham's terminal building as a counterpart to the U.S. Post Office to the west. Still another would assure a uniform design on the east side of Second Street to give the Capitol Grounds a distinct border.

The plan fails, in my view, to provide for urbanity and amenity -- the cafes and kioks such a large tourist attraction needs. The Capitol Hill residents oppose commercial activities on the Capitol compound. But what is wrong with a few news or hot dog stands if they are properly designed?

More important, perhaps, is the plan's failure to come to terms with the Supreme Court problem. The present building has become too small. Expansion is possible by annexing the Methodist Building, north of it. But that does not seem desirable. Should we not build a new Supreme Court somewhere else as a symbol that the judiciary is distinct from the legislative branch of government?

Architect Paul Rudolph wrote in 1963: "Somehow the Supreme Court ended up, not as an integral part of a great plan, but merely at the back door of the Capitol, with no relationship to the Capitol itself. Even more insulting, it parodies the Capitol buildings in a ridiculous way."

Rudolph is right. Perhaps the time has come to correct this historic error. If a new Supreme Court is built elsewhere, architect Call Gilbert's temple might be used as a "Knowledge Center" of the Library of Congress, a prospect that makes Librarian Daniel Boorstin's heart leap.

Discussion of the master plan is bound to raise other such challenges. It is a great and much needed opportunity for Congress to take a good look at itself and its public image.