John F. Kennedy once said of Washington, “It has Northern charm and Southern efficiency.” That, of course, was when it was a sleepy place lacking much air conditioning and before the bureaucratic explosion brought on by Lyndon Johnson’s and Richard Nixon’s many new programs. These caused a building boom that only now is slowing down.

Nearly every week, it seemed, an old building was being gutted or razed for a new one. Ever since the mid-Sixties ever more companies, trade associations and issue-oriented organizations have flocked to Washington to set up listening and lobbying posts. The city’s population, declining for several years as families fled to the suburbs, has been growing since 2000. It is now over 600,000 with many young people moving in to be closer to work. 

With the prospect of downtown Washington seeming to run out of building space for new buildings, Democratic Mayor Vincent Gray and Republican Rep. Darrell Issa, chairman of the House Oversight and Government Reform Committee, have been considering the unthinkable: raising the capital’s century-old building height limit of 130 feet (12 stories in most cases). Cheering them on are property developers. The Downtown D.C. Business Improvement District thinks that the central area will be built out within a dozen or so years. That is, if trends of the last few decades continue. Such predictions are being made against a background of steady talk on Capitol Hill of curbing the growth of the federal government.

The Messrs. Gray and Issa are talking about possibly raising the downtown height limit by 15 feet, allowing an extra story for existing buildings. Ominously, though, outside the downtown, there is talk of allowing heights well above that. Not so fast, says George Clark, chairman of a preservation group, the Committee of 100. He says the scale of Washington is unique among American cities and emphasizes its monumental nature.

That’s what the current height limit is all about. It was inspired by the open feeling of central Paris. It has kept the focus on the city’s monuments and the U.S. Capitol (only the Washington Monument exceeds the height limit). In Paris, when the need arose for many new office buildings, a new area, La Défense, was created about a dozen miles away for high-rises. Washington already has its La Défense, right across the river in Rosslyn, Virginia, where the high-rise office buildings provide a nice — but arm’s-length — backdrop to the city.

For several years, I had frequent one-day business trips to New York from Washington, always taking the train. While I like New York’s tempo and scale, the best part of the day was stepping out of Union Station back in Washington in the early evening and drinking in the reassuring, comfortable human scale of the city. My first thought was always, “I’m home.”

Will builders be the kings of construction in the capital city? There is no certainty that office building demand of the last three decades will continue indefinitely. Here’s a way to put the Gray-Issa proposal to rest: Shrink the federal government, let more office buildings go up in Rosslyn and leave Washington’s scale just as it is.

Mr. Hannaford worked in Washington for 25 years.