The diffusion literature is replete with examples of highly salient policies spreading across subnational governments. However, low-salience policies that do not benefit from a groundswell of public opinion also spread across jurisdictions in patterns that appear similar to those of other, more well-known policy ideas. This research is an investigation of the mechanisms that propagate low-salience policies. I analyze the adoption of the U.S. Green Building Council's (USGBC) Leadership in Energy Efficient Design standard across 119 U.S. cities from 2000 to 2008. The investigation indicates that a knowledge broker, in this case the USGBC, occupies critical roles in linking a low-salience policy to a broader set of widely held societal values, developing a common policy vocabulary, providing a base policy that jurisdictions may freely adapt, and creating a diffusion infrastructure by acting as a communication hub for existing and interested jurisdictions to discuss innovations and progress.