If the federal government were only to honor its past commitments, it could go far toward helping this city out of its present financial dilemma.

The commitment, first made in former president Nixon's 1972 speech about the Forthcoming Bicentennial, was to locate federal offices for 5,000 to 10,000 federal workers in the proposed Fort Lincoln New Town in Northeast Washington.

This promise was reaffirmed in April 1973, when the Office of Management and Budget told a congressional committee that a million square feet of leasable office space was planned for Fort Lincoln, located at Bladensburg Road and South Dakota Avenue.

The space is needed for example by the National Oceanic and Atmospheric Administration and other agencies whose staff is now scattered in rented space all over the metropolitan area.

In the past the General Services Administration, which is in charge of housing most federal bureaucracies, has contributed heavily to the blight of the national capital by leasing offices out in the suburbs. This means, of course, that the city is deprived of potential tax revenue and jobs for workers who find it hard to commute long distances or to find homes in suburbia. It also deprives the city of the lunch-hour business from thousands of middle-income workers.

Most of these federally spawned office concentrations -- like Crystal City, Rossyln and Parklawn -- are architectural disasters, ugly, inefficient, jerry-built and expensive to maintain.

They force employes to burn large amounts of gasoline commuting to work and in consulting with colleagues in other scattered offices.

The reasons for this horrendous waste are mostly sinister. Back in the Eisenhower days, government decentralization was federal policy. It was to keep us going in the event of an atomic attack on downtown Washington. But on second thought, being governed from Gaithersburg did not promise to get us very far either, so the federal government declared itself opposed to wasteful urban sprawl and in favor of urban concentration.

But then Congress cut appropriations for federal buildings and GSA rented, rather than built, needed office space. The developers of leased buildings are in favor of urban sprawl because remote undeveloped land is cheaper than land with roads and sewers.

Some agency heads, lets face it, also like to be away from the wicked city. Some irregularities in GSA lease arrangements have been proved. But as Sen. Daniel Patrick Moynihan (D-N.Y.) has pointed out, the whole idea is irregular and incredibly expensive for the government, the city and federal workers. A Moynihan bill would have GSA build its own buildings and locate them where efficiency and public interest demand. But it may be some time until the bill passes.

The Fort Lincoln site is available now. New federal offices in a pleasant and easily accessible environment could be ready for occupancy in two years or less. Several hundred families live in Fort Lincoln already and its developer, Theodore, R. Hagans Jr., is ready to build the community's town center.

As planned by architects Bryant & Bryant, the Fort Lincoln Town Center is to embrace an 11-acre manmade lake to be built by the D. C. Department of Housing and Urban Development under a long-approved urban renewal grant. The center is to consist of a mix of highrise offices and condominium apartments, townhouses, shops, restaurants and a large supermarket badly needed by the entire region. There is also to be a 350-room hotel.

All this, if it comes off anywhere near as well as it was conceived, would make a most pleasant environment for NOAA and other federal agencies. Twice as large as Crystal City, it would be only half as crowded and would feature many amenities along the lake as well as recreational and open space.The site, with its hills, trees and views, is probably the most attractive left in the city.

By car, one gets speedily to Fort Lincoln both from the city and the suburbs. There are to be 4,000 parking places.

Plans also call for a public-transportation link to the Rhode Island Avenue Metrorail station, a 2 1/2 mile round trip. A $50,000 feasibility study will determine whether shuttle buses, a monorail or perhaps streetcars are most cost-beneficial.

Fort Lincoln has been a ridiculous Alfonse and Gaston act ever since a 1967 executive order by President Lyndon Johnson called for a new town there. Any number of federal and District government agencies, citizen groups, developers and planners dreamed, planned, quarreled and got nowhere until Hagans finally got started.

If the long-promised 1 million square feet of federal office space in Fort Lincoln's Town Centers are finally contracted for, says Robert L. Moore, the city's housing and urban development chief, it would instantly trigger construction of another million square feet of private office space. The tax yield to the District would be at least $4 million a year. It would create 12,000 jobs. And it would assure some 4,000 units of housing with a real-estate tax revenue of another $3 million a year.

But that is not all: If Fort Lincoln at last becomes a place where people work and play as well as live, it will provide impetus for attractive new industrial plants and other job opportunities along New York Avenue, the primary gateway to the nation's capital.