We extend Elitzur's theorem to systems with symmetries intermediate between
global and local. In general, our theorem formalizes the idea of {\it
dimensional reduction}. We apply the results of this generalization to many
systems that are of current interest. These include liquid crystalline phases
of Quantum Hall systems, orbital systems, geometrically frustrated spin
lattices, Bose metals, and models of superconducting arrays.Comment: 10 pages, 1 figur