THE D.C. ZONING Commission is trying to decide whether the Washington Hilton Hotel should be allowed to expand its facilities into the surrounding Adams-Morgan neighborhood. At stake, for neighborhood residents, are three apartment buildings with 225 units housing 269 people. Residents argue that the larger hotel will cause increased traffic, further squeeze the housing supply in the area and strike a killing blow to the cosmopolitan character of the neighborhood. At stake for the city, the Barry administration contends, are the added jobs the hotel's expansion would bring to the area and the additional space to accommodate the increased numbers of tourists who are expected to come to the city once the convention center is completed.

James O. Gibson, assistant city administrator for planning and development, says the city has weighed the competing interests of hotels and residents and intends to protect most housing from hotel expansion while allowing the Hilton and some others to expand. His proposal is to prohibit new hotel construction in most residential zones, as well to prohibit conversion of apartment houses to hotels in residential and some commercial areas. About 1,500 apartments have been converted for hotel use recently, according to the city government, as landlords -- prohibited by law in some cases from converting to condominiums -- attempt to get around the District's inhibitng rent-control law.

Under the proposal, the Hilton, located on Connecticut Avenue, would be allowed to expand to contiguous lots because its main entrance is on a "principal arterial street," or street that is a major thoroughfaree in and out of the city. Although groups oppposing the Hilton's expansion claim that 16 other hotels could follow, Mr. Gibson says only one other hotel in the city, the Fairfax Hotel on Massachusetts Avenue, is in a location where such expansion is feasible. For that reason, Mr. Gibson is considering asking the zoning commission to grant the Hilton and the Fairfax special exceptions to the zoning law instead of requesting that the code be rewritten.

Two interests of the city are in conflict here. One is the need to create solid neighborhoods with reasonably priced housing; the other is the desirability of encouraging hotels to build in the city so that they can hire more District workers, pay more District taxes and accommodate the expected increase in visitors to the city.

But Adams-Morgan is already one of the city's most vital neighborhoods with a rare mix of ethnic groups and people of all income levels. Affordable housing, however, is in critically short supply and high-priced. Many apartment buildings have converted to condominiums. Reducing the amount of housing cannot benefit the neighborhoods, which enjoys a fairly thriving economy.

And the expansion of the Hilton will not necessarily increase the number of hotel rooms or jobs in the city. Mr. Gibson says his office has been unable to get a firm proposal from the Hilton as to the use (restaurant ballroom, auditorium or gallery) it plans to make of the additional space. Regardless of the Hilton's plans, Mr. Gibson says, the city will have a sufficient growth in the number of hotels in the city for at least the next 15 years. The growth could get better as more hotels decide to come to Washington as a result of the convention center.

For that reason, the need to expand the Hilton becomes questionable. The expansion holds no clear benefit either to the Adams-Morgan community or the city as a whole. The zoning board should reject the proposal to allow the hotel to expand.