In a redeveloping city, where space is scarce and small squabbles over any piece of property has the potential to turn into a large heated community debate, the city’s lack of available national monumental space could dominate the District’s urban development discourse for much of the 21st century.

On Monday, Post columnist Fred Hiatt, making the case for a “third-century Mall,” gives us some historical perspective. As the nation has grown, so has the National Mall. A century ago, the Mall ended roughly at 17th Street, where it met the Potomac’s swampy tidal flats.

Doubters predicted that no one would venture into the new swampland. But over the century the Lincoln and Jefferson memorials, Vietnam Veterans Memorial and Constitution Gardens have proven the “new” Mall reasonably popular.

And so we have the current Mall, now filled to capacity. Hiatt says that the “third century” Mall should stretch southward through East Potomac Park, cross the Washington Channel into Southwest D.C. and then tie into the giant Anacostia waterfront redevelopment scheme and the yet-to-be-reshaped South Capitol Street corridor.

Quite an ambitious plan. The National Capital Planning Commission‘s “new” Mall planning initiative, “Extending the Legacy” has some interesting ideas. Where do you think the Mall should grow?