Among urbanists in America, the advent of landmark-preservation laws in the 1960s is usually viewed as an inspiring time in urban planning: Concerned communities, academics, and fans of architecture banded together to protect beloved old buildings from the grand plans of rich developers and powerful politicians. And, remarkably enough, the Davids usually defeated the Goliaths. But have they acquired too much power? So say a growing contingent of critics who believe preservation has gotten out of hand. They include left-leaning economic policy wonks, architects, and architectural critics.