There's an inconvenient truth that preservationists typically gloss over in their ever-more-pressing fight to save mid-20th Century modernist buildings from demolition: Many (though certainly not all) of these buildings are tough to love.

Perhaps it's their cool abstraction, or their labyrinthine floor plans, or their harsh materials, like the serrated concrete that can practically cut your skin. Whatever the reason, the American public has yet to cotton to these buildings. A survey of America's 150 favorite works of architecture, released last February, didn't contain a single structure by Chicago's master of steel and glass, Ludwig Mies van der Rohe.

But popularity is one thing; quality is another. A half century ago, when Space Age America was infatuated with all things new, there wasn't yet broad-based popular support for preserving old Victorian houses or Beaux Arts train stations that evoked the grandeur of ancient Rome. They were, like today's threatened mid-century modernist buildings, too old to be new and too new to be old. And so, they were shortsightedly torn down. Now the question is whether we're about to make the same mistake again.