Washington Post article about the restrictive building height limits in the city:
"D.C. leaders should consider lifting the limit around Metro stations that serve commuters from across the region, such as Dupont Circle, Union Station, Metro Center, the Navy Yard and, yes, Friendship Heights."
Common sense tells us that high density zoning centered around mass transit hubs (e.g. Metro stops) is the only way to fight suburban and exurban sprawl. If you can't build up, you have to build out.