Ayn Rand’s spirit seems to be returning to haunt us all, infusing downright bizarre criteria into today’s increasingly heated debate over preserving modernist buildings. The preservationists, naturally enough, want to protect everything designed by the Howard Roark-style, celebrated modernist architects who argued they were erecting pure buildings in a compromising world. Buildings by original Bauhaus architects like Joseph Urban are on everyone’s list, as are most buildings by Yale brutalist, Paul Rudolph.

But the preservationists are also lobbying to landmark buildings by the real life equivalents of Roark’s protagonist, Peter Keating, whose mediocrity was rewarded by major design contracts while Roark was expelled from New York. Buildings by Philip Johnson, for example, often thought to be the model for Keating, are now showing up on most preservationist lists, even though almost no one would claim these buildings are illustrious. Since landmarking has the effect of rigidifying current use and preventing evolutionary change, New Yorkers need to pay close attention to this debate.

The Municipal Art Society’s watch list of 30 Under 30 includes, for example, the egregious Marriott Marquis Hotel designed by John Portman, the immense IBM Building designed by Edward Larrabee Barnes, and Philip Johnson’s cathedral-size AT&T/Sony Building. Do New Yorkers really want these structures pre-empting all future uses? Are we confident enough of their merit to protect them into perpetuity? Will Walter Gropius’s MetLife Building, looming over Grand Central Terminal, be next on the list of buildings to be protected?

The problem is that modernist architects espoused a good number of truly bad ideas, which are far more important than their familiar contempt for color and ornamentation. At its most fundamental, modernist architecture intended to break with the past, defy the streetscape, and rend the urban fabric. In urging that buildings be landmarked, preservationists are not merely advancing the benefits of modernism’s clean, uncluttered lines. They argue the benefits of what are often modernism’s depredations, such as the super block.

Of course, some of the debate will be settled by deterioration. As a Yale architectural historian, Vincent Scully, pointed out in 1999, modernists embraced an aesthetic of impermanence – with the result that most of their buildings will not survive because they were poorly built. Mies van der Rohe may have defined architecture as the will of an epoch translated into space, but much of that will is crumbling beneath its shoddy materials.

Many of the finest modernist buildings have already been landmarked. Joseph’s Urban’s sublime New School for Social Research, for example, on West 12th Street, is protected by an individual designation. Mayer, Whittlesley & Glass’s Butterfield House, across the street, is protected by the overarching of the Greenwich Village Historic District. The best-known modernist buildings were designated when they became eligible. Gordon Bunshaft’s 1952 Lever House on Park Avenue, for example, was designated a landmark in 1983, a year after eligibility.

Here are a few worthy, undesignated buildings for public discussion:

The Edgar J. Kaufmann Conference Rooms in the penthouse of 809 U.N. Plaza make up one of only three projects in the country designed by Alvar Aalto, the Finnish architect. The rooms were commissioned in 1963 by Edgar J. Kaufmann Jr., the first curator of industrial design at the Museum of Modern Art and the son of the couple who had commissioned Frank Lloyd Wright to design Fallingwater in Pennsylvania. The rooms are a small masterpiece, notes a preservation advocate with the Preservation League of New York, Caroline Rob Zaleski. “Anywhere else in the world, these rooms would be a monument,” she says.

The Tracey Towers Apartments at 40 West Mosholu Parkway in the Bedford Park section of the Bronx, designed by Paul Rudolph and Jerold Karlen, were built between 1967 and 1972. In these moderate-income apartment towers that opened in 1974, Rudolph deliberately mimicked the striated surface of the Art and Architecture Building he had designed for Yale. Somehow, though, they are far more pleasing. This is no minor matter since they were financed under the state’s Mitchell-Lama program, which severely restricted “extras” in design and architecture in order to keep costs down for moderate-income households. A fellow with the Municipal Art Society, Vicki Weiner, notes that Rudolph successfully worked out the design problems of high-rise living in an urban neighborhood.

Citicorp Center at 153 E. 53rd St. in Midtown, designed by Hugh Stubbins and completed in 1977, was built during the fiscal crisis that nearly bankrupted New York. Though its engineering proved to be seriously flawed, its social mixture worked well: corporate offices above with St. Peter’s Church and jazz center, a landscaped courtyard and galleria, and a beautifully constructed subway station below. An architect who also oversees the Web site nyc-architecture.com, Tom Fletcher, calls the church “an anchor of serenity” and the building itself a “bold presence” that helped revitalize a tired commercial area.

The Asphalt Green Aqua Center at 1750 York Ave. was designed by Richard Dattner and completed in 1993. Asphalt Green is so much fun and would be instantly recognized if the landmarks commission had enjoyability as a criterion. The original Municipal Asphalt Plant, with its parabolic arch structure, was designed by Kahn & Jacobs and opened in 1944. In 1968, the city tried to demolish Asphalt Green, which Robert Moses had called “the most hideous waterfront structure ever inflicted on a city.” Instead, it was reconfigured by Hellmuth, Obata & Kassabaum into a sports center that opened in 1982. After much neighborhood agitation, Asphalt Green and the sports center were redesigned into the current complex.

Like Asphalt Green, the city itself needs to adapt, preserving what’s best and discarding what’s not. Modernist buildings should be kept or rejected on their merits – not because they’re symbols of their time, or because eminent architects designed them. Eminent modernists chose to slash New York’s urban fabric with many of their buildings, only a few of which are worthy of the city they damaged.